DAMASK_EICMD/code/constitutive_dislotwin.f90

! Copyright 2011 Max-Planck-Institut für Eisenforschung GmbH
!
! This file is part of DAMASK,
! the Düsseldorf Advanced MAterial Simulation Kit.
!
! DAMASK is free software: you can redistribute it and/or modify
! it under the terms of the GNU General Public License as published by
! the Free Software Foundation, either version 3 of the License, or
! (at your option) any later version.
!
! DAMASK is distributed in the hope that it will be useful,
! but WITHOUT ANY WARRANTY; without even the implied warranty of
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
! GNU General Public License for more details.
!
! You should have received a copy of the GNU General Public License
! along with DAMASK. If not, see <http://www.gnu.org/licenses/>.
!
!##############################################################
!* $Id$
!************************************
!*      Module: CONSTITUTIVE        *
!************************************

MODULE constitutive_dislotwin

!* Include other modules
use prec, only: pReal,pInt
implicit none

!* Lists of states and physical parameters
character(len=*), parameter :: constitutive_dislotwin_label = 'dislotwin'
character(len=18), dimension(2), parameter:: constitutive_dislotwin_listBasicSlipStates = (/'rhoEdge   ', &
                                                                                            'rhoEdgeDip'/)
character(len=18), dimension(1), parameter:: constitutive_dislotwin_listBasicTwinStates = (/'twinFraction'/)
character(len=18), dimension(4), parameter:: constitutive_dislotwin_listDependentSlipStates =(/'invLambdaSlip    ', &
                                                                                               'invLambdaSlipTwin', &
                                                                                               'meanFreePathSlip ', &
                                                                                               'tauSlipThreshold '/)
character(len=18), dimension(4), parameter:: constitutive_dislotwin_listDependentTwinStates =(/'invLambdaTwin   ', &
                                                                                               'meanFreePathTwin', &
                                                                                               'tauTwinThreshold', &
                                                                                               'twinVolume      '/)
real(pReal), parameter :: kB = 1.38e-23_pReal ! Boltzmann constant in J/Kelvin

!* Definition of global variables
integer(pInt),     dimension(:),           allocatable :: constitutive_dislotwin_sizeDotState, &                ! number of dotStates
                                                          constitutive_dislotwin_sizeState, &                   ! total number of microstructural state variables
                                                          constitutive_dislotwin_sizePostResults                ! cumulative size of post results
integer(pInt),     dimension(:,:), allocatable, target :: constitutive_dislotwin_sizePostResult                 ! size of each post result output
character(len=64), dimension(:,:), allocatable, target :: constitutive_dislotwin_output                         ! name of each post result output
integer(pInt),     dimension(:),           allocatable :: constitutive_dislotwin_Noutput                        ! number of outputs per instance of this plasticity 
character(len=32), dimension(:),           allocatable :: constitutive_dislotwin_structureName                  ! name of the lattice structure
integer(pInt),     dimension(:),           allocatable :: constitutive_dislotwin_structure, &                   ! number representing the kind of lattice structure
                                                          constitutive_dislotwin_totalNslip, &                  ! total number of active slip systems for each instance
                                                          constitutive_dislotwin_totalNtwin                     ! total number of active twin systems for each instance
integer(pInt),     dimension(:,:),         allocatable :: constitutive_dislotwin_Nslip, &                       ! number of active slip systems for each family and instance
                                                          constitutive_dislotwin_Ntwin                          ! number of active twin systems for each family and instance
real(pReal),       dimension(:),           allocatable :: constitutive_dislotwin_CoverA, &                      ! c/a ratio for hex type lattice
                                                          constitutive_dislotwin_C11, &                         ! C11 element in elasticity matrix
                                                          constitutive_dislotwin_C12, &                         ! C12 element in elasticity matrix
                                                          constitutive_dislotwin_C13, &                         ! C13 element in elasticity matrix
                                                          constitutive_dislotwin_C33, &                         ! C33 element in elasticity matrix
                                                          constitutive_dislotwin_C44, &                         ! C44 element in elasticity matrix
                                                          constitutive_dislotwin_Gmod, &                        ! shear modulus
                                                          constitutive_dislotwin_CAtomicVolume, &               ! atomic volume in Bugers vector unit
                                                          constitutive_dislotwin_D0, &                          ! prefactor for self-diffusion coefficient
                                                          constitutive_dislotwin_Qsd, &                         ! activation energy for dislocation climb
                                                          constitutive_dislotwin_GrainSize, &                   ! grain size
                                                          constitutive_dislotwin_p, &                           ! p-exponent in glide velocity
                                                          constitutive_dislotwin_q, &                           ! q-exponent in glide velocity
                                                          constitutive_dislotwin_MaxTwinFraction, &             ! maximum allowed total twin volume fraction
                                                          constitutive_dislotwin_r, &                           ! r-exponent in twin nucleation rate
                                                          constitutive_dislotwin_CEdgeDipMinDistance, &         !
                                                          constitutive_dislotwin_Cmfptwin, &                    !
                                                          constitutive_dislotwin_Cthresholdtwin, &              !
                                                          constitutive_dislotwin_SolidSolutionStrength, &       ! Strength due to elements in solid solution
                                                          constitutive_dislotwin_L0, &                          ! Length of twin nuclei in Burgers vectors
                                                          constitutive_dislotwin_sbResistance, &                ! FIXED (for now) value for shearband resistance (might become an internal state variable at some point)
                                                          constitutive_dislotwin_sbVelocity, &                  ! FIXED (for now) value for shearband velocity_0
                                                          constitutive_dislotwin_sbQedge, &                     ! FIXED (for now) value for shearband systems Qedge
                                                          constitutive_dislotwin_SFE_0K, &                      ! stacking fault energy at zero K
                                                          constitutive_dislotwin_dSFE_dT, &                     ! temperature dependance of stacking fault energy
                                                          constitutive_dislotwin_aTolRho                        ! absolute tolerance for integration of dislocation density
real(pReal),       dimension(:,:,:),       allocatable :: constitutive_dislotwin_Cslip_66                       ! elasticity matrix in Mandel notation for each instance
real(pReal),       dimension(:,:,:,:),     allocatable :: constitutive_dislotwin_Ctwin_66                       ! twin elasticity matrix in Mandel notation for each instance
real(pReal),       dimension(:,:,:,:,:),   allocatable :: constitutive_dislotwin_Cslip_3333                     ! elasticity matrix for each instance
real(pReal),       dimension(:,:,:,:,:,:), allocatable :: constitutive_dislotwin_Ctwin_3333                     ! twin elasticity matrix for each instance
real(pReal),       dimension(:,:),         allocatable :: constitutive_dislotwin_rhoEdge0, &                    ! initial edge dislocation density per slip system for each family and instance
                                                          constitutive_dislotwin_rhoEdgeDip0, &                 ! initial edge dipole density per slip system for each family and instance
                                                          constitutive_dislotwin_burgersPerSlipFamily, &        ! absolute length of burgers vector [m] for each slip family and instance
                                                          constitutive_dislotwin_burgersPerSlipSystem, &        ! absolute length of burgers vector [m] for each slip system and instance
                                                          constitutive_dislotwin_burgersPerTwinFamily, &        ! absolute length of burgers vector [m] for each twin family and instance
                                                          constitutive_dislotwin_burgersPerTwinSystem, &        ! absolute length of burgers vector [m] for each twin system and instance
                                                          constitutive_dislotwin_QedgePerSlipFamily, &          ! activation energy for glide [J] for each slip family and instance
                                                          constitutive_dislotwin_QedgePerSlipSystem, &          ! activation energy for glide [J] for each slip system and instance
                                                          constitutive_dislotwin_v0PerSlipFamily, &             ! dislocation velocity prefactor [m/s] for each family and instance
                                                          constitutive_dislotwin_v0PerSlipSystem, &             ! dislocation velocity prefactor [m/s] for each slip system and instance
                                                          constitutive_dislotwin_Ndot0PerTwinFamily, &          ! twin nucleation rate [1/m³s] for each twin family and instance
                                                          constitutive_dislotwin_Ndot0PerTwinSystem, &          ! twin nucleation rate [1/m³s] for each twin system and instance
                                                          constitutive_dislotwin_twinsizePerTwinFamily, &       ! twin thickness [m] for each twin family and instance
                                                          constitutive_dislotwin_twinsizePerTwinSystem, &       ! twin thickness [m] for each twin system and instance
                                                          constitutive_dislotwin_CLambdaSlipPerSlipFamily, &    ! Adj. parameter for distance between 2 forest dislocations for each slip family and instance
                                                          constitutive_dislotwin_CLambdaSlipPerSlipSystem, &    ! Adj. parameter for distance between 2 forest dislocations for each slip system and instance
                                                          constitutive_dislotwin_interaction_SlipSlip, &        ! coefficients for slip-slip interaction for each interaction type and instance
                                                          constitutive_dislotwin_interaction_SlipTwin, &        ! coefficients for slip-twin interaction for each interaction type and instance
                                                          constitutive_dislotwin_interaction_TwinSlip, &        ! coefficients for twin-slip interaction for each interaction type and instance
                                                          constitutive_dislotwin_interaction_TwinTwin           ! coefficients for twin-twin interaction for each interaction type and instance
real(pReal),       dimension(:,:,:),       allocatable :: constitutive_dislotwin_interactionMatrix_SlipSlip, &  ! interaction matrix of the different slip systems for each instance
                                                          constitutive_dislotwin_interactionMatrix_SlipTwin, &  ! interaction matrix of slip systems with twin systems for each instance
                                                          constitutive_dislotwin_interactionMatrix_TwinSlip, &  ! interaction matrix of twin systems with slip systems for each instance
                                                          constitutive_dislotwin_interactionMatrix_TwinTwin, &  ! interaction matrix of the different twin systems for each instance
                                                          constitutive_dislotwin_forestProjectionEdge           ! matrix of forest projections of edge dislocations for each instance
real(pReal),       dimension(:,:,:,:,:),   allocatable :: constitutive_dislotwin_sbSv

CONTAINS
!****************************************
!* - constitutive_dislotwin_init
!* - constitutive_dislotwin_stateInit
!* - constitutive_dislotwin_relevantState
!* - constitutive_dislotwin_homogenizedC
!* - constitutive_dislotwin_microstructure
!* - constitutive_dislotwin_LpAndItsTangent
!* - constitutive_dislotwin_dotState
!* - constitutive_dislotwin_deltaState
!* - constitutive_dislotwin_dotTemperature
!* - constitutive_dislotwin_postResults
!****************************************

subroutine constitutive_dislotwin_init(file)
!**************************************
!*      Module initialization         *
!**************************************
use, intrinsic :: iso_fortran_env                                ! to get compiler_version and compiler_options (at least for gfortran 4.6 at the moment)
use prec,    only: pInt,pReal
use math,    only: math_Mandel3333to66,math_Voigt66to3333,math_mul3x3
use mesh,    only: mesh_maxNips, mesh_NcpElems
use IO
use material
use lattice

!* Input variables
integer(pInt), intent(in) :: file
!* Local variables
integer(pInt), parameter :: maxNchunks = 21_pInt
integer(pInt), dimension(1+2*maxNchunks) :: positions
integer(pInt) :: section, maxNinstance,mySize,myStructure,maxTotalNslip,maxTotalNtwin,&
                 f,i,j,k,l,m,n,o,p,q,r,s,ns,nt, &
                 index_myFamily, index_otherFamily
character(len=64) tag
character(len=1024) :: line = ''                                                                   ! to start initialized
 
write(6,*)
write(6,*) '<<<+-  constitutive_',trim(constitutive_dislotwin_label),' init  -+>>>'
write(6,*) '$Id$'
#include "compilation_info.f90"

maxNinstance = int(count(phase_plasticity == constitutive_dislotwin_label),pInt)
if (maxNinstance == 0_pInt) return

!* Space allocation for global variables
allocate(constitutive_dislotwin_sizeDotState(maxNinstance))
         constitutive_dislotwin_sizeDotState = 0_pInt
allocate(constitutive_dislotwin_sizeState(maxNinstance))
         constitutive_dislotwin_sizeState = 0_pInt
allocate(constitutive_dislotwin_sizePostResults(maxNinstance))
         constitutive_dislotwin_sizePostResults = 0_pInt
allocate(constitutive_dislotwin_sizePostResult(maxval(phase_Noutput),maxNinstance))
         constitutive_dislotwin_sizePostResult  = 0_pInt
allocate(constitutive_dislotwin_output(maxval(phase_Noutput),maxNinstance))
         constitutive_dislotwin_output = ''
allocate(constitutive_dislotwin_Noutput(maxNinstance))
         constitutive_dislotwin_Noutput = 0_pInt

allocate(constitutive_dislotwin_structureName(maxNinstance))
         constitutive_dislotwin_structureName = ''
allocate(constitutive_dislotwin_structure(maxNinstance))
         constitutive_dislotwin_structure = 0_pInt
allocate(constitutive_dislotwin_Nslip(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_Nslip = 0_pInt
allocate(constitutive_dislotwin_Ntwin(lattice_maxNtwinFamily,maxNinstance))
         constitutive_dislotwin_Ntwin = 0_pInt
allocate(constitutive_dislotwin_totalNslip(maxNinstance))
         constitutive_dislotwin_totalNslip  = 0_pInt
allocate(constitutive_dislotwin_totalNtwin(maxNinstance))
         constitutive_dislotwin_totalNtwin = 0_pInt
allocate(constitutive_dislotwin_CoverA(maxNinstance))
         constitutive_dislotwin_CoverA = 0.0_pReal
allocate(constitutive_dislotwin_C11(maxNinstance))
         constitutive_dislotwin_C11 = 0.0_pReal
allocate(constitutive_dislotwin_C12(maxNinstance))
         constitutive_dislotwin_C12 = 0.0_pReal
allocate(constitutive_dislotwin_C13(maxNinstance))
         constitutive_dislotwin_C13 = 0.0_pReal
allocate(constitutive_dislotwin_C33(maxNinstance))
         constitutive_dislotwin_C33 = 0.0_pReal
allocate(constitutive_dislotwin_C44(maxNinstance))
         constitutive_dislotwin_C44 = 0.0_pReal
allocate(constitutive_dislotwin_Gmod(maxNinstance))
         constitutive_dislotwin_Gmod = 0.0_pReal
allocate(constitutive_dislotwin_CAtomicVolume(maxNinstance))
         constitutive_dislotwin_CAtomicVolume = 0.0_pReal
allocate(constitutive_dislotwin_D0(maxNinstance))
         constitutive_dislotwin_D0 = 0.0_pReal
allocate(constitutive_dislotwin_Qsd(maxNinstance))
         constitutive_dislotwin_Qsd = 0.0_pReal
allocate(constitutive_dislotwin_GrainSize(maxNinstance))
         constitutive_dislotwin_GrainSize = 0.0_pReal
allocate(constitutive_dislotwin_p(maxNinstance))
         constitutive_dislotwin_p = 0.0_pReal
allocate(constitutive_dislotwin_q(maxNinstance))
         constitutive_dislotwin_q = 0.0_pReal
allocate(constitutive_dislotwin_MaxTwinFraction(maxNinstance))
         constitutive_dislotwin_MaxTwinFraction = 0.0_pReal
allocate(constitutive_dislotwin_r(maxNinstance))
         constitutive_dislotwin_r = 0.0_pReal
allocate(constitutive_dislotwin_CEdgeDipMinDistance(maxNinstance))
         constitutive_dislotwin_CEdgeDipMinDistance  = 0.0_pReal
allocate(constitutive_dislotwin_Cmfptwin(maxNinstance))
         constitutive_dislotwin_Cmfptwin = 0.0_pReal
allocate(constitutive_dislotwin_Cthresholdtwin(maxNinstance))
         constitutive_dislotwin_Cthresholdtwin = 0.0_pReal
allocate(constitutive_dislotwin_SolidSolutionStrength(maxNinstance))
         constitutive_dislotwin_SolidSolutionStrength = 0.0_pReal
allocate(constitutive_dislotwin_L0(maxNinstance))
         constitutive_dislotwin_L0 = 0.0_pReal
allocate(constitutive_dislotwin_aTolRho(maxNinstance))
         constitutive_dislotwin_aTolRho = 0.0_pReal
allocate(constitutive_dislotwin_Cslip_66(6,6,maxNinstance))
         constitutive_dislotwin_Cslip_66 = 0.0_pReal
allocate(constitutive_dislotwin_Cslip_3333(3,3,3,3,maxNinstance))
         constitutive_dislotwin_Cslip_3333 = 0.0_pReal
allocate(constitutive_dislotwin_sbResistance(maxNinstance))
         constitutive_dislotwin_sbResistance = 0.0_pReal
allocate(constitutive_dislotwin_sbVelocity(maxNinstance))
         constitutive_dislotwin_sbVelocity = 0.0_pReal
allocate(constitutive_dislotwin_sbQedge(maxNinstance))
         constitutive_dislotwin_sbQedge = 0.0_pReal
allocate(constitutive_dislotwin_SFE_0K(maxNinstance))
         constitutive_dislotwin_SFE_0K = 0.0_pReal
allocate(constitutive_dislotwin_dSFE_dT(maxNinstance))
         constitutive_dislotwin_dSFE_dT = 0.0_pReal
allocate(constitutive_dislotwin_rhoEdge0(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_rhoEdge0 = 0.0_pReal
allocate(constitutive_dislotwin_rhoEdgeDip0(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_rhoEdgeDip0 = 0.0_pReal
allocate(constitutive_dislotwin_burgersPerSlipFamily(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_burgersPerSlipFamily = 0.0_pReal
allocate(constitutive_dislotwin_burgersPerTwinFamily(lattice_maxNtwinFamily,maxNinstance))
         constitutive_dislotwin_burgersPerTwinFamily = 0.0_pReal
allocate(constitutive_dislotwin_QedgePerSlipFamily(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_QedgePerSlipFamily = 0.0_pReal
allocate(constitutive_dislotwin_v0PerSlipFamily(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_v0PerSlipFamily = 0.0_pReal
allocate(constitutive_dislotwin_Ndot0PerTwinFamily(lattice_maxNtwinFamily,maxNinstance))
         constitutive_dislotwin_Ndot0PerTwinFamily = 0.0_pReal
allocate(constitutive_dislotwin_twinsizePerTwinFamily(lattice_maxNtwinFamily,maxNinstance))
         constitutive_dislotwin_twinsizePerTwinFamily = 0.0_pReal
allocate(constitutive_dislotwin_CLambdaSlipPerSlipFamily(lattice_maxNslipFamily,maxNinstance))
         constitutive_dislotwin_CLambdaSlipPerSlipFamily = 0.0_pReal
allocate(constitutive_dislotwin_interaction_SlipSlip(lattice_maxNinteraction,maxNinstance))
         constitutive_dislotwin_interaction_SlipSlip = 0.0_pReal
allocate(constitutive_dislotwin_interaction_SlipTwin(lattice_maxNinteraction,maxNinstance))
         constitutive_dislotwin_interaction_SlipTwin = 0.0_pReal
allocate(constitutive_dislotwin_interaction_TwinSlip(lattice_maxNinteraction,maxNinstance))
         constitutive_dislotwin_interaction_TwinSlip = 0.0_pReal
allocate(constitutive_dislotwin_interaction_TwinTwin(lattice_maxNinteraction,maxNinstance))
         constitutive_dislotwin_interaction_TwinTwin = 0.0_pReal
allocate(constitutive_dislotwin_sbSv(6,6,homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems))
         constitutive_dislotwin_sbSv = 0.0_pReal

!* Readout data from material.config file
rewind(file)
line = ''
section = 0_pInt

do while (IO_lc(IO_getTag(line,'<','>')) /= 'phase')     ! wind forward to <phase>
   read(file,'(a1024)',END=100) line
enddo

do                                                       ! read thru sections of phase part
   read(file,'(a1024)',END=100) line
   if (IO_isBlank(line)) cycle                           ! skip empty lines
   if (IO_getTag(line,'<','>') /= '') exit               ! stop at next part
   if (IO_getTag(line,'[',']') /= '') then               ! next section
     section = section + 1_pInt                          ! advance section counter
     cycle
   endif
   if (section > 0_pInt .and. phase_plasticity(section) == constitutive_dislotwin_label) then  ! one of my sections
     i = phase_plasticityInstance(section)               ! which instance of my plasticity is present phase
     positions = IO_stringPos(line,maxNchunks)
     tag = IO_lc(IO_stringValue(line,positions,1_pInt))        ! extract key
     select case(tag)
       case ('plasticity', 'elasticity')
         cycle
       case ('(output)')
         constitutive_dislotwin_Noutput(i) = constitutive_dislotwin_Noutput(i) + 1_pInt
         constitutive_dislotwin_output(constitutive_dislotwin_Noutput(i),i) = IO_lc(IO_stringValue(line,positions,2_pInt))
       case ('lattice_structure')
              constitutive_dislotwin_structureName(i) = IO_lc(IO_stringValue(line,positions,2_pInt))
       case ('covera_ratio')
              constitutive_dislotwin_CoverA(i) = IO_floatValue(line,positions,2_pInt)
       case ('c11')
              constitutive_dislotwin_C11(i) = IO_floatValue(line,positions,2_pInt)
       case ('c12')
              constitutive_dislotwin_C12(i) = IO_floatValue(line,positions,2_pInt)
       case ('c13')
              constitutive_dislotwin_C13(i) = IO_floatValue(line,positions,2_pInt)
       case ('c33')
              constitutive_dislotwin_C33(i) = IO_floatValue(line,positions,2_pInt)
       case ('c44')
              constitutive_dislotwin_C44(i) = IO_floatValue(line,positions,2_pInt)
       case ('nslip')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_Nslip(j,i) = IO_intValue(line,positions,1_pInt+j)
       case ('ntwin')
              forall (j = 1_pInt:lattice_maxNtwinFamily) &
                constitutive_dislotwin_Ntwin(j,i) = IO_intValue(line,positions,1_pInt+j)
       case ('rhoedge0')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_rhoEdge0(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('rhoedgedip0')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_rhoEdgeDip0(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('slipburgers')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_burgersPerSlipFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('twinburgers')
              forall (j = 1_pInt:lattice_maxNtwinFamily) &
                constitutive_dislotwin_burgersPerTwinFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('qedge')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_QedgePerSlipFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('v0')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_v0PerSlipFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('ndot0')
              forall (j = 1_pInt:lattice_maxNtwinFamily) &
                constitutive_dislotwin_Ndot0PerTwinFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('twinsize')
              forall (j = 1_pInt:lattice_maxNtwinFamily) &
                constitutive_dislotwin_twinsizePerTwinFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('clambdaslip')
              forall (j = 1_pInt:lattice_maxNslipFamily) &
                constitutive_dislotwin_CLambdaSlipPerSlipFamily(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('grainsize')
              constitutive_dislotwin_GrainSize(i) = IO_floatValue(line,positions,2_pInt)
       case ('maxtwinfraction')
              constitutive_dislotwin_MaxTwinFraction(i) = IO_floatValue(line,positions,2_pInt)
       case ('pexponent')
              constitutive_dislotwin_p(i) = IO_floatValue(line,positions,2_pInt)
       case ('qexponent')
              constitutive_dislotwin_q(i) = IO_floatValue(line,positions,2_pInt)
       case ('rexponent')
              constitutive_dislotwin_r(i) = IO_floatValue(line,positions,2_pInt)
       case ('d0')
              constitutive_dislotwin_D0(i) = IO_floatValue(line,positions,2_pInt)
       case ('qsd')
              constitutive_dislotwin_Qsd(i) = IO_floatValue(line,positions,2_pInt)
       case ('atol_rho')
              constitutive_dislotwin_aTolRho(i) = IO_floatValue(line,positions,2_pInt)
       case ('cmfptwin')
              constitutive_dislotwin_Cmfptwin(i) = IO_floatValue(line,positions,2_pInt)
       case ('cthresholdtwin')
              constitutive_dislotwin_Cthresholdtwin(i) = IO_floatValue(line,positions,2_pInt)
       case ('solidsolutionstrength')
              constitutive_dislotwin_SolidSolutionStrength(i) = IO_floatValue(line,positions,2_pInt)
       case ('l0')
              constitutive_dislotwin_L0(i) = IO_floatValue(line,positions,2_pInt)
       case ('cedgedipmindistance')
              constitutive_dislotwin_CEdgeDipMinDistance(i) = IO_floatValue(line,positions,2_pInt)
       case ('catomicvolume')
              constitutive_dislotwin_CAtomicVolume(i) = IO_floatValue(line,positions,2_pInt)
       case ('interaction_slipslip','interactionslipslip')
              forall (j = 1_pInt:lattice_maxNinteraction) &
                constitutive_dislotwin_interaction_SlipSlip(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('interaction_sliptwin','interactionsliptwin')
              forall (j = 1_pInt:lattice_maxNinteraction) &
                constitutive_dislotwin_interaction_SlipTwin(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('interaction_twinslip','interactiontwinslip')
              forall (j = 1_pInt:lattice_maxNinteraction) &
                constitutive_dislotwin_interaction_TwinSlip(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('interaction_twintwin','interactiontwintwin')
              forall (j = 1_pInt:lattice_maxNinteraction) &
                constitutive_dislotwin_interaction_TwinTwin(j,i) = IO_floatValue(line,positions,1_pInt+j)
       case ('sfe_0k')
              constitutive_dislotwin_SFE_0K(i) = IO_floatValue(line,positions,2_pInt)
       case ('dsfe_dt')
              constitutive_dislotwin_dSFE_dT(i) = IO_floatValue(line,positions,2_pInt)
       case ('shearbandresistance')
              constitutive_dislotwin_sbResistance(i) = IO_floatValue(line,positions,2_pInt)
       case ('shearbandvelocity')
              constitutive_dislotwin_sbVelocity(i) = IO_floatValue(line,positions,2_pInt)
       case ('qedgepersbsystem')
              constitutive_dislotwin_sbQedge(i) = IO_floatValue(line,positions,2_pInt)
       case default
              call IO_error(210_pInt,ext_msg=tag//' ('//constitutive_dislotwin_label//')')
     end select
   endif
enddo

100 do i = 1_pInt,maxNinstance
   constitutive_dislotwin_structure(i) = &
   lattice_initializeStructure(constitutive_dislotwin_structureName(i),constitutive_dislotwin_CoverA(i))
   myStructure = constitutive_dislotwin_structure(i)

   !* Sanity checks
   if (myStructure < 1_pInt)                                                call IO_error(205_pInt,e=i)
   if (sum(constitutive_dislotwin_Nslip(:,i)) < 0_pInt)                     call IO_error(211_pInt,e=i,ext_msg='Nslip (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (sum(constitutive_dislotwin_Ntwin(:,i)) < 0_pInt)                     call IO_error(211_pInt,e=i,ext_msg='Ntwin (' &
                                                                                 //constitutive_dislotwin_label//')')
   do f = 1_pInt,lattice_maxNslipFamily
     if (constitutive_dislotwin_Nslip(f,i) > 0_pInt) then
       if (constitutive_dislotwin_rhoEdge0(f,i) < 0.0_pReal)                call IO_error(211_pInt,e=i,ext_msg='rhoEdge0 (' &
                                                                                 //constitutive_dislotwin_label//')')
       if (constitutive_dislotwin_rhoEdgeDip0(f,i) < 0.0_pReal)             call IO_error(211_pInt,e=i,ext_msg='rhoEdgeDip0 (' &
                                                                                 //constitutive_dislotwin_label//')')
       if (constitutive_dislotwin_burgersPerSlipFamily(f,i) <= 0.0_pReal)   call IO_error(211_pInt,e=i,ext_msg='slipBurgers (' &
                                                                                 //constitutive_dislotwin_label//')')
       if (constitutive_dislotwin_v0PerSlipFamily(f,i) <= 0.0_pReal)        call IO_error(211_pInt,e=i,ext_msg='v0 (' &
                                                                                 //constitutive_dislotwin_label//')')
     endif
   enddo
   do f = 1_pInt,lattice_maxNtwinFamily
     if (constitutive_dislotwin_Ntwin(f,i) > 0_pInt) then
       if (constitutive_dislotwin_burgersPerTwinFamily(f,i) <= 0.0_pReal)   call IO_error(211_pInt,e=i,ext_msg='twinburgers (' &
                                                                                 //constitutive_dislotwin_label//')')
       if (constitutive_dislotwin_Ndot0PerTwinFamily(f,i) < 0.0_pReal)      call IO_error(211_pInt,e=i,ext_msg='ndot0 (' &
                                                                                 //constitutive_dislotwin_label//')')
     endif
   enddo
   if (constitutive_dislotwin_CAtomicVolume(i) <= 0.0_pReal)                call IO_error(211_pInt,e=i,ext_msg='cAtomicVolume (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_D0(i) <= 0.0_pReal)                           call IO_error(211_pInt,e=i,ext_msg='D0 (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_Qsd(i) <= 0.0_pReal)                          call IO_error(211_pInt,e=i,ext_msg='Qsd (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_aTolRho(i) <= 0.0_pReal)                      call IO_error(211_pInt,e=i,ext_msg='aTolRho (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_sbResistance(i) <= 0.0_pReal)                 call IO_error(211_pInt,e=i,ext_msg='sbResistance (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_sbVelocity(i) < 0.0_pReal)                    call IO_error(211_pInt,e=i,ext_msg='sbVelocity (' &
                                                                                 //constitutive_dislotwin_label//')')
   if (constitutive_dislotwin_SFE_0K(i) == 0.0_pReal .AND. &
       constitutive_dislotwin_dSFE_dT(i) == 0.0_pReal)                      call IO_error(211_pInt,e=i,ext_msg='SFE (' &
                                                                                 //constitutive_dislotwin_label//')')

   !* Determine total number of active slip or twin systems
   constitutive_dislotwin_Nslip(:,i) = min(lattice_NslipSystem(:,myStructure),constitutive_dislotwin_Nslip(:,i))
   constitutive_dislotwin_Ntwin(:,i) = min(lattice_NtwinSystem(:,myStructure),constitutive_dislotwin_Ntwin(:,i))
   constitutive_dislotwin_totalNslip(i) = sum(constitutive_dislotwin_Nslip(:,i))
   constitutive_dislotwin_totalNtwin(i) = sum(constitutive_dislotwin_Ntwin(:,i))

enddo

!* Allocation of variables whose size depends on the total number of active slip systems
maxTotalNslip = maxval(constitutive_dislotwin_totalNslip)
maxTotalNtwin = maxval(constitutive_dislotwin_totalNtwin)

!write(6,*) 'nslip',i,constitutive_dislotwin_totalNslip(i),maxTotalNslip
!write(6,*) 'ntwin',i,constitutive_dislotwin_totalNtwin(i),maxTotalNtwin

allocate(constitutive_dislotwin_burgersPerSlipSystem(maxTotalNslip, maxNinstance))
         constitutive_dislotwin_burgersPerSlipSystem = 0.0_pReal
allocate(constitutive_dislotwin_burgersPerTwinSystem(maxTotalNtwin, maxNinstance))
         constitutive_dislotwin_burgersPerTwinSystem= 0.0_pReal
allocate(constitutive_dislotwin_QedgePerSlipSystem(maxTotalNslip, maxNinstance))
         constitutive_dislotwin_QedgePerSlipSystem = 0.0_pReal
allocate(constitutive_dislotwin_v0PerSlipSystem(maxTotalNslip, maxNinstance))
         constitutive_dislotwin_v0PerSlipSystem = 0.0_pReal
allocate(constitutive_dislotwin_Ndot0PerTwinSystem(maxTotalNtwin, maxNinstance))
         constitutive_dislotwin_Ndot0PerTwinSystem = 0.0_pReal
allocate(constitutive_dislotwin_twinsizePerTwinSystem(maxTotalNtwin, maxNinstance))
         constitutive_dislotwin_twinsizePerTwinSystem = 0.0_pReal
allocate(constitutive_dislotwin_CLambdaSlipPerSlipSystem(maxTotalNslip, maxNinstance))
         constitutive_dislotwin_CLambdaSlipPerSlipSystem = 0.0_pReal

allocate(constitutive_dislotwin_interactionMatrix_SlipSlip(maxTotalNslip,maxTotalNslip,maxNinstance))
         constitutive_dislotwin_interactionMatrix_SlipSlip = 0.0_pReal
allocate(constitutive_dislotwin_interactionMatrix_SlipTwin(maxTotalNslip,maxTotalNtwin,maxNinstance))
         constitutive_dislotwin_interactionMatrix_SlipTwin = 0.0_pReal
allocate(constitutive_dislotwin_interactionMatrix_TwinSlip(maxTotalNtwin,maxTotalNslip,maxNinstance))
         constitutive_dislotwin_interactionMatrix_TwinSlip = 0.0_pReal
allocate(constitutive_dislotwin_interactionMatrix_TwinTwin(maxTotalNtwin,maxTotalNtwin,maxNinstance))
         constitutive_dislotwin_interactionMatrix_TwinTwin = 0.0_pReal
allocate(constitutive_dislotwin_forestProjectionEdge(maxTotalNslip,maxTotalNslip,maxNinstance))
         constitutive_dislotwin_forestProjectionEdge = 0.0_pReal

allocate(constitutive_dislotwin_Ctwin_66(6,6,maxTotalNtwin,maxNinstance))
         constitutive_dislotwin_Ctwin_66 = 0.0_pReal
allocate(constitutive_dislotwin_Ctwin_3333(3,3,3,3,maxTotalNtwin,maxNinstance))
         constitutive_dislotwin_Ctwin_3333 = 0.0_pReal

do i = 1_pInt,maxNinstance
   myStructure = constitutive_dislotwin_structure(i)

   ns = constitutive_dislotwin_totalNslip(i)
   nt = constitutive_dislotwin_totalNtwin(i)
   !  write(6,*) 'instance',i,'has nslip and ntwin',ns,nt

   !* Determine size of state array

   constitutive_dislotwin_sizeDotState(i) = int(size(constitutive_dislotwin_listBasicSlipStates),pInt) * ns &
                                          + int(size(constitutive_dislotwin_listBasicTwinStates),pInt) * nt
   constitutive_dislotwin_sizeState(i) = constitutive_dislotwin_sizeDotState(i) &
                                       + int(size(constitutive_dislotwin_listDependentSlipStates),pInt) * ns &
                                       + int(size(constitutive_dislotwin_listDependentTwinStates),pInt) * nt

   !* Determine size of postResults array
   do o = 1_pInt,constitutive_dislotwin_Noutput(i)
      select case(constitutive_dislotwin_output(o,i))
        case('edge_density', &
             'dipole_density', &
             'shear_rate_slip', &
             'mfp_slip', &
             'resolved_stress_slip', &
             'threshold_stress_slip', &
             'edge_dipole_distance', &
             'stress_exponent' &
             )
           mySize = ns
        case('twin_fraction', &
             'shear_rate_twin', &
             'mfp_twin', &
             'resolved_stress_twin', &
             'threshold_stress_twin' &
             )
           mySize = nt
        case('resolved_stress_shearband', &
             'shear_rate_shearband' &
             )
           mySize = 6_pInt
        case('schmid_factor_shearband')
           mySize = 6_pInt
        case('sb_eigenvalues')
           mySize = 3_pInt  
        case('sb_eigenvectors')
           mySize = 9_pInt  
        case default
           call IO_error(212_pInt,ext_msg=constitutive_dislotwin_output(o,i)//' ('//constitutive_dislotwin_label//')')
      end select

       if (mySize > 0_pInt) then  ! any meaningful output found
          constitutive_dislotwin_sizePostResult(o,i) = mySize
          constitutive_dislotwin_sizePostResults(i)  = constitutive_dislotwin_sizePostResults(i) + mySize
       endif
   enddo

    
   !* Elasticity matrix and shear modulus according to material.config
   select case (myStructure)
   case(1_pInt:2_pInt) ! cubic(s)
     forall(k=1_pInt:3_pInt)
       forall(j=1_pInt:3_pInt) &
         constitutive_dislotwin_Cslip_66(k,j,i)               = constitutive_dislotwin_C12(i)
         constitutive_dislotwin_Cslip_66(k,k,i)               = constitutive_dislotwin_C11(i)
         constitutive_dislotwin_Cslip_66(k+3_pInt,k+3_pInt,i) = constitutive_dislotwin_C44(i)
     end forall
   case(3_pInt:)       ! all hex
     constitutive_dislotwin_Cslip_66(1,1,i) = constitutive_dislotwin_C11(i)
     constitutive_dislotwin_Cslip_66(2,2,i) = constitutive_dislotwin_C11(i)
     constitutive_dislotwin_Cslip_66(3,3,i) = constitutive_dislotwin_C33(i)
     constitutive_dislotwin_Cslip_66(1,2,i) = constitutive_dislotwin_C12(i)
     constitutive_dislotwin_Cslip_66(2,1,i) = constitutive_dislotwin_C12(i)
     constitutive_dislotwin_Cslip_66(1,3,i) = constitutive_dislotwin_C13(i)
     constitutive_dislotwin_Cslip_66(3,1,i) = constitutive_dislotwin_C13(i)
     constitutive_dislotwin_Cslip_66(2,3,i) = constitutive_dislotwin_C13(i)
     constitutive_dislotwin_Cslip_66(3,2,i) = constitutive_dislotwin_C13(i)
     constitutive_dislotwin_Cslip_66(4,4,i) = constitutive_dislotwin_C44(i)
     constitutive_dislotwin_Cslip_66(5,5,i) = constitutive_dislotwin_C44(i)
     constitutive_dislotwin_Cslip_66(6,6,i) = 0.5_pReal*(constitutive_dislotwin_C11(i)-constitutive_dislotwin_C12(i))
   end select
   constitutive_dislotwin_Cslip_66(:,:,i) = math_Mandel3333to66(math_Voigt66to3333(constitutive_dislotwin_Cslip_66(:,:,i)))
   constitutive_dislotwin_Cslip_3333(:,:,:,:,i) = math_Voigt66to3333(constitutive_dislotwin_Cslip_66(:,:,i))
   constitutive_dislotwin_Gmod(i) = &
   0.2_pReal*(constitutive_dislotwin_C11(i)-constitutive_dislotwin_C12(i))+0.3_pReal*constitutive_dislotwin_C44(i)


   !* Process slip related parameters ------------------------------------------------

   do f = 1_pInt,lattice_maxNslipFamily
     index_myFamily = sum(constitutive_dislotwin_Nslip(1:f-1_pInt,i))                              ! index in truncated slip system list

     do j = 1_pInt,constitutive_dislotwin_Nslip(f,i)                                               ! system in family

     !* Burgers vector, 
     !  dislocation velocity prefactor,
     !  mean free path prefactor,
     !  and minimum dipole distance

       constitutive_dislotwin_burgersPerSlipSystem(index_myFamily+j,i)     = constitutive_dislotwin_burgersPerSlipFamily(f,i)
       constitutive_dislotwin_QedgePerSlipSystem(index_myFamily+j,i)       = constitutive_dislotwin_QedgePerSlipFamily(f,i)
       constitutive_dislotwin_v0PerSlipSystem(index_myFamily+j,i)          = constitutive_dislotwin_v0PerSlipFamily(f,i)
       constitutive_dislotwin_CLambdaSlipPerSlipSystem(index_myFamily+j,i) = constitutive_dislotwin_CLambdaSlipPerSlipFamily(f,i)

     !* Interaction matrices

       do o = 1_pInt,lattice_maxNslipFamily
         index_otherFamily = sum(constitutive_dislotwin_Nslip(1:o-1_pInt,i))
         do k = 1_pInt,constitutive_dislotwin_Nslip(o,i)                                           ! loop over (active) systems in other family (slip)
           constitutive_dislotwin_interactionMatrix_SlipSlip(index_myFamily+j,index_otherFamily+k,i) = &
                 constitutive_dislotwin_interaction_SlipSlip(lattice_interactionSlipSlip( &
                                                               sum(lattice_NslipSystem(1:f-1,myStructure))+j, &
                                                               sum(lattice_NslipSystem(1:o-1,myStructure))+k, &
                                                               myStructure), i )
       enddo; enddo

       do o = 1_pInt,lattice_maxNtwinFamily
         index_otherFamily = sum(constitutive_dislotwin_Ntwin(1:o-1_pInt,i))
         do k = 1_pInt,constitutive_dislotwin_Ntwin(o,i)                                           ! loop over (active) systems in other family (twin)
           constitutive_dislotwin_interactionMatrix_SlipTwin(index_myFamily+j,index_otherFamily+k,i) = &
                 constitutive_dislotwin_interaction_SlipTwin(lattice_interactionSlipTwin( &
                                                               sum(lattice_NslipSystem(1:f-1_pInt,myStructure))+j, &
                                                               sum(lattice_NtwinSystem(1:o-1_pInt,myStructure))+k, &
                                                               myStructure), i )
       enddo; enddo

     enddo ! slip system in family
   enddo   ! slip families

   !* Process twin related parameters ------------------------------------------------
   
   do f = 1_pInt,lattice_maxNtwinFamily
     index_myFamily = sum(constitutive_dislotwin_Ntwin(1:f-1_pInt,i))                              ! index in truncated twin system list

     do j = 1_pInt,constitutive_dislotwin_Ntwin(f,i)                                               ! system in family

     !* Burgers vector,
     !  nucleation rate prefactor,
     !  and twin size

       constitutive_dislotwin_burgersPerTwinSystem(index_myFamily+j,i)  = constitutive_dislotwin_burgersPerTwinFamily(f,i)
       constitutive_dislotwin_Ndot0PerTwinSystem(index_myFamily+j,i)    = constitutive_dislotwin_Ndot0PerTwinFamily(f,i)
       constitutive_dislotwin_twinsizePerTwinSystem(index_myFamily+j,i) = constitutive_dislotwin_twinsizePerTwinFamily(f,i)

     !* Rotate twin elasticity matrices

       index_otherFamily = sum(lattice_NtwinSystem(1:f-1_pInt,myStructure))                        ! index in full lattice twin list
       do l = 1_pInt,3_pInt ; do m = 1_pInt,3_pInt ; do n = 1_pInt,3_pInt ; do o = 1_pInt,3_pInt
         do p = 1_pInt,3_pInt ; do q = 1_pInt,3_pInt ; do r = 1_pInt,3_pInt ; do s = 1_pInt,3_pInt
           constitutive_dislotwin_Ctwin_3333(l,m,n,o,index_myFamily+j,i) = &
           constitutive_dislotwin_Ctwin_3333(l,m,n,o,index_myFamily+j,i) + &
             constitutive_dislotwin_Cslip_3333(p,q,r,s,i) * &
             lattice_Qtwin(l,p,index_otherFamily+j,myStructure) * &
             lattice_Qtwin(m,q,index_otherFamily+j,myStructure) * &
             lattice_Qtwin(n,r,index_otherFamily+j,myStructure) * &
             lattice_Qtwin(o,s,index_otherFamily+j,myStructure)
         enddo ; enddo ; enddo ; enddo
       enddo ; enddo ; enddo ; enddo
       constitutive_dislotwin_Ctwin_66(:,:,index_myFamily+j,i) = math_Mandel3333to66(constitutive_dislotwin_Ctwin_3333(:,:,:,:,index_myFamily+j,i))

    !* Interaction matrices

       do o = 1_pInt,lattice_maxNslipFamily
         index_otherFamily = sum(constitutive_dislotwin_Nslip(1:o-1_pInt,i))
         do k = 1_pInt,constitutive_dislotwin_Nslip(o,i)                                           ! loop over (active) systems in other family (slip)
           constitutive_dislotwin_interactionMatrix_TwinSlip(index_myFamily+j,index_otherFamily+k,i) = &
                 constitutive_dislotwin_interaction_TwinSlip(lattice_interactionTwinSlip( &
                                                               sum(lattice_NtwinSystem(1:f-1_pInt,myStructure))+j, &
                                                               sum(lattice_NslipSystem(1:o-1_pInt,myStructure))+k, &
                                                               myStructure), i )
       enddo; enddo

       do o = 1_pInt,lattice_maxNtwinFamily
         index_otherFamily = sum(constitutive_dislotwin_Ntwin(1:o-1_pInt,i))
         do k = 1_pInt,constitutive_dislotwin_Ntwin(o,i)                                           ! loop over (active) systems in other family (twin)
           constitutive_dislotwin_interactionMatrix_TwinTwin(index_myFamily+j,index_otherFamily+k,i) = &
                 constitutive_dislotwin_interaction_TwinTwin(lattice_interactionTwinTwin( &
                                                               sum(lattice_NtwinSystem(1:f-1_pInt,myStructure))+j, &
                                                               sum(lattice_NtwinSystem(1:o-1_pInt,myStructure))+k, &
                                                               myStructure), i )
       enddo; enddo

     enddo  ! twin system in family
   enddo    ! twin families

enddo  ! instances

end subroutine


function constitutive_dislotwin_stateInit(myInstance)
!*********************************************************************
!* initial microstructural state                                     *
!*********************************************************************
use prec,    only: pReal,pInt
use math,    only: pi
use lattice, only: lattice_maxNslipFamily
implicit none

!* Input-Output variables
integer(pInt) :: myInstance
real(pReal), dimension(constitutive_dislotwin_sizeState(myInstance))  :: constitutive_dislotwin_stateInit
!* Local variables
integer(pInt) :: i,j,f,ns,nt, index_myFamily
real(pReal), dimension(constitutive_dislotwin_totalNslip(myInstance)) :: rhoEdge0, &
                                                                         rhoEdgeDip0, &
                                                                         invLambdaSlip0, &
                                                                         MeanFreePathSlip0, &
                                                                         tauSlipThreshold0
real(pReal), dimension(constitutive_dislotwin_totalNtwin(myInstance)) :: MeanFreePathTwin0,TwinVolume0

ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)
constitutive_dislotwin_stateInit = 0.0_pReal

!* Initialize basic slip state variables

do f = 1_pInt,lattice_maxNslipFamily
  index_myFamily   = sum(constitutive_dislotwin_Nslip(1:f-1_pInt,myInstance))                      ! index in truncated slip system list
  rhoEdge0(index_myFamily+1_pInt: &
           index_myFamily+constitutive_dislotwin_Nslip(f,myInstance)) = &
    constitutive_dislotwin_rhoEdge0(f,myInstance)
  rhoEdgeDip0(index_myFamily+1_pInt: &
              index_myFamily+constitutive_dislotwin_Nslip(f,myInstance)) = &
    constitutive_dislotwin_rhoEdgeDip0(f,myInstance)
enddo

constitutive_dislotwin_stateInit(1_pInt:ns)           = rhoEdge0
constitutive_dislotwin_stateInit(ns+1_pInt:2_pInt*ns) = rhoEdgeDip0

!* Initialize dependent slip microstructural variables
forall (i = 1_pInt:ns) &
  invLambdaSlip0(i) = sqrt(dot_product((rhoEdge0+rhoEdgeDip0),constitutive_dislotwin_forestProjectionEdge(1:ns,i,myInstance)))/ &
                      constitutive_dislotwin_CLambdaSlipPerSlipSystem(i,myInstance)
constitutive_dislotwin_stateInit(2_pInt*ns+nt+1_pInt:3_pInt*ns+nt) = invLambdaSlip0

forall (i = 1_pInt:ns) &
  MeanFreePathSlip0(i) = &
    constitutive_dislotwin_GrainSize(myInstance)/(1.0_pReal+invLambdaSlip0(i)*constitutive_dislotwin_GrainSize(myInstance))
constitutive_dislotwin_stateInit(4_pInt*ns+2_pInt*nt+1:5_pInt*ns+2_pInt*nt) = MeanFreePathSlip0

forall (i = 1_pInt:ns) &
  tauSlipThreshold0(i) = constitutive_dislotwin_SolidSolutionStrength(myInstance) + &
    constitutive_dislotwin_Gmod(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(i,myInstance) * &
    sqrt(dot_product((rhoEdge0+rhoEdgeDip0),constitutive_dislotwin_interactionMatrix_SlipSlip(i,1:ns,myInstance)))
constitutive_dislotwin_stateInit(5_pInt*ns+3_pInt*nt+1:6_pInt*ns+3_pInt*nt) = tauSlipThreshold0

!* Initialize dependent twin microstructural variables
forall (j = 1_pInt:nt) &
  MeanFreePathTwin0(j) = constitutive_dislotwin_GrainSize(myInstance)
constitutive_dislotwin_stateInit(5_pInt*ns+2_pInt*nt+1_pInt:5_pInt*ns+3_pInt*nt) = MeanFreePathTwin0

forall (j = 1_pInt:nt) &
  TwinVolume0(j) = &
    (pi/6.0_pReal)*constitutive_dislotwin_twinsizePerTwinSystem(j,myInstance)*MeanFreePathTwin0(j)**(2.0_pReal)
constitutive_dislotwin_stateInit(6_pInt*ns+4_pInt*nt+1_pInt:6_pInt*ns+5_pInt*nt) = TwinVolume0

!write(6,*) '#STATEINIT#'
!write(6,*)
!write(6,'(a,/,4(3(f30.20,1x)/))') 'RhoEdge',rhoEdge0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'RhoEdgedip',rhoEdgeDip0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'invLambdaSlip',invLambdaSlip0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'MeanFreePathSlip',MeanFreePathSlip0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'tauSlipThreshold', tauSlipThreshold0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'MeanFreePathTwin', MeanFreePathTwin0
!write(6,'(a,/,4(3(f30.20,1x)/))') 'TwinVolume', TwinVolume0

end function


pure function constitutive_dislotwin_aTolState(myInstance)
!*********************************************************************
!* absolute state tolerance                                          *
!*********************************************************************
use prec,     only: pReal, pInt
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: myInstance
real(pReal), dimension(constitutive_dislotwin_sizeState(myInstance)) :: constitutive_dislotwin_aTolState

constitutive_dislotwin_aTolState = constitutive_dislotwin_aTolRho(myInstance)

end function constitutive_dislotwin_aTolState


pure function constitutive_dislotwin_homogenizedC(state,g,ip,el)
!*********************************************************************
!* calculates homogenized elacticity matrix                          *
!*  - state           : microstructure quantities                    *
!*  - g               : component-ID of current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec
use mesh,     only: mesh_NcpElems,mesh_maxNips
use material, only: homogenization_maxNgrains,material_phase,phase_plasticityInstance
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: g,ip,el
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(in) :: state
real(pReal), dimension(6,6) :: constitutive_dislotwin_homogenizedC
!* Local variables
integer(pInt) myInstance,ns,nt,i
real(pReal) sumf

!* Shortened notation
myInstance = phase_plasticityInstance(material_phase(g,ip,el))
ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)

!* Total twin volume fraction
sumf = sum(state(g,ip,el)%p((2_pInt*ns+1_pInt):(2_pInt*ns+nt))) ! safe for nt == 0

!* Homogenized elasticity matrix
constitutive_dislotwin_homogenizedC = (1.0_pReal-sumf)*constitutive_dislotwin_Cslip_66(:,:,myInstance)
do i=1_pInt,nt
   constitutive_dislotwin_homogenizedC = &
   constitutive_dislotwin_homogenizedC + state(g,ip,el)%p(2_pInt*ns+i)*constitutive_dislotwin_Ctwin_66(:,:,i,myInstance)
enddo

end function


subroutine constitutive_dislotwin_microstructure(Temperature,state,g,ip,el)
!*********************************************************************
!* calculates quantities characterizing the microstructure           *
!*  - Temperature     : temperature                                  *
!*  - state           : microstructure quantities                    *
!*  - ipc             : component-ID of current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec
use math,     only: pi
use mesh,     only: mesh_NcpElems,mesh_maxNips
use material, only: homogenization_maxNgrains,material_phase,phase_plasticityInstance
!use debug,    only: debugger
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: g,ip,el
real(pReal), intent(in) :: Temperature
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(inout) :: state
!* Local variables
integer(pInt) myInstance,myStructure,ns,nt,s,t
real(pReal) sumf,sfe
real(pReal), dimension(constitutive_dislotwin_totalNtwin(phase_plasticityInstance(material_phase(g,ip,el)))) :: fOverStacksize

!* Shortened notation
myInstance = phase_plasticityInstance(material_phase(g,ip,el))
myStructure = constitutive_dislotwin_structure(myInstance)
ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)
!* State: 1           :  ns         rho_edge
!* State: ns+1        :  2*ns       rho_dipole
!* State: 2*ns+1      :  2*ns+nt    f
!* State: 2*ns+nt+1   :  3*ns+nt    1/lambda_slip
!* State: 3*ns+nt+1   :  4*ns+nt    1/lambda_sliptwin
!* State: 4*ns+nt+1   :  4*ns+2*nt  1/lambda_twin
!* State: 4*ns+2*nt+1 :  5*ns+2*nt  mfp_slip
!* State: 5*ns+2*nt+1 :  5*ns+3*nt  mfp_twin
!* State: 5*ns+3*nt+1 :  6*ns+3*nt  threshold_stress_slip
!* State: 6*ns+3*nt+1 :  6*ns+4*nt  threshold_stress_twin
!* State: 6*ns+4*nt+1 :  6*ns+5*nt  twin volume

!* Total twin volume fraction
sumf = sum(state(g,ip,el)%p((2*ns+1):(2*ns+nt))) ! safe for nt == 0

!* Stacking fault energy
sfe = constitutive_dislotwin_SFE_0K(myInstance) + & 
      constitutive_dislotwin_dSFE_dT(myInstance) * Temperature

!* rescaled twin volume fraction for topology
forall (t = 1_pInt:nt) &
  fOverStacksize(t) = &
    state(g,ip,el)%p(2_pInt*ns+t)/constitutive_dislotwin_twinsizePerTwinSystem(t,myInstance)

!* 1/mean free distance between 2 forest dislocations seen by a moving dislocation
forall (s = 1_pInt:ns) &
  state(g,ip,el)%p(2_pInt*ns+nt+s) = &
    sqrt(dot_product((state(g,ip,el)%p(1:ns)+state(g,ip,el)%p(ns+1_pInt:2_pInt*ns)),&
                     constitutive_dislotwin_forestProjectionEdge(1:ns,s,myInstance)))/ &
    constitutive_dislotwin_CLambdaSlipPerSlipSystem(s,myInstance)

!* 1/mean free distance between 2 twin stacks from different systems seen by a moving dislocation
!$OMP CRITICAL (evilmatmul)
state(g,ip,el)%p((3_pInt*ns+nt+1_pInt):(4_pInt*ns+nt)) = 0.0_pReal
if (nt > 0_pInt) &
  state(g,ip,el)%p((3_pInt*ns+nt+1):(4_pInt*ns+nt)) = &
    matmul(constitutive_dislotwin_interactionMatrix_SlipTwin(1:ns,1:nt,myInstance),fOverStacksize(1:nt))/(1.0_pReal-sumf)
!$OMP END CRITICAL (evilmatmul)

!* 1/mean free distance between 2 twin stacks from different systems seen by a growing twin
!$OMP CRITICAL (evilmatmul)
if (nt > 0_pInt) &
  state(g,ip,el)%p((4_pInt*ns+nt+1_pInt):(4_pInt*ns+2_pInt*nt)) = &
    matmul(constitutive_dislotwin_interactionMatrix_TwinTwin(1:nt,1:nt,myInstance),fOverStacksize(1:nt))/(1.0_pReal-sumf)
!$OMP END CRITICAL (evilmatmul)

!* mean free path between 2 obstacles seen by a moving dislocation
do s = 1_pInt,ns
   if (nt > 0_pInt) then
      state(g,ip,el)%p(4_pInt*ns+2_pInt*nt+s) = &
        constitutive_dislotwin_GrainSize(myInstance)/(1.0_pReal+constitutive_dislotwin_GrainSize(myInstance)*&
        (state(g,ip,el)%p(2_pInt*ns+nt+s)+state(g,ip,el)%p(3_pInt*ns+nt+s)))
   else
      state(g,ip,el)%p(4_pInt*ns+s) = &
        constitutive_dislotwin_GrainSize(myInstance)/&
        (1.0_pReal+constitutive_dislotwin_GrainSize(myInstance)*(state(g,ip,el)%p(2_pInt*ns+s)))
   endif
enddo

!* mean free path between 2 obstacles seen by a growing twin
forall (t = 1_pInt:nt) &
  state(g,ip,el)%p(5_pInt*ns+2_pInt*nt+t) = &
    (constitutive_dislotwin_Cmfptwin(myInstance)*constitutive_dislotwin_GrainSize(myInstance))/&
    (1.0_pReal+constitutive_dislotwin_GrainSize(myInstance)*state(g,ip,el)%p(4_pInt*ns+nt+t))

!* threshold stress for dislocation motion
forall (s = 1_pInt:ns) &
  state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+s) = constitutive_dislotwin_SolidSolutionStrength(myInstance)+ &
    constitutive_dislotwin_Gmod(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(s,myInstance)*&
    sqrt(dot_product((state(g,ip,el)%p(1:ns)+state(g,ip,el)%p(ns+1_pInt:2_pInt*ns)),&
                     constitutive_dislotwin_interactionMatrix_SlipSlip(s,1:ns,myInstance)))

!* threshold stress for growing twin
forall (t = 1_pInt:nt) &
  state(g,ip,el)%p(6_pInt*ns+3_pInt*nt+t) = &
    constitutive_dislotwin_Cthresholdtwin(myInstance)*&
    (sfe/(3.0_pReal*constitutive_dislotwin_burgersPerTwinSystem(t,myInstance))+&
    3.0_pReal*constitutive_dislotwin_burgersPerTwinSystem(t,myInstance)*constitutive_dislotwin_Gmod(myInstance)/&
    (constitutive_dislotwin_L0(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(t,myInstance)))

!* final twin volume after growth
forall (t = 1_pInt:nt) &
  state(g,ip,el)%p(6_pInt*ns+4_pInt*nt+t) = &
    (pi/6.0_pReal)*constitutive_dislotwin_twinsizePerTwinSystem(t,myInstance)*state(g,ip,el)%p(5*ns+2*nt+t)**(2.0_pReal)

!if ((ip==1).and.(el==1)) then
!   write(6,*) '#MICROSTRUCTURE#'
! write(6,*)
! write(6,'(a,/,4(3(f10.4,1x)/))') 'rhoEdge',state(g,ip,el)%p(1:ns)/1e9
! write(6,'(a,/,4(3(f10.4,1x)/))') 'rhoEdgeDip',state(g,ip,el)%p(ns+1:2*ns)/1e9
! write(6,'(a,/,4(3(f10.4,1x)/))') 'Fraction',state(g,ip,el)%p(2*ns+1:2*ns+nt)
!endif

end subroutine


subroutine constitutive_dislotwin_LpAndItsTangent(Lp,dLp_dTstar,Tstar_v,Temperature,state,g,ip,el)
!*********************************************************************
!* calculates plastic velocity gradient and its tangent              *
!* INPUT:                                                            *
!*  - Temperature     : temperature                                  *
!*  - state           : microstructure quantities                    *
!*  - Tstar_v         : 2nd Piola Kirchhoff stress tensor (Mandel)   *
!*  - ipc             : component-ID at current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!* OUTPUT:                                                           *
!*  - Lp              : plastic velocity gradient                    *
!*  - dLp_dTstar      : derivative of Lp (4th-rank tensor)           *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec
use math,     only: math_Plain3333to99, math_Mandel6to33, math_Mandel33to6, &
                    math_spectralDecompositionSym33, math_tensorproduct, math_symmetric33,math_mul33x3
use mesh,     only: mesh_NcpElems,mesh_maxNips
use material, only: homogenization_maxNgrains,material_phase,phase_plasticityInstance
use lattice,  only: lattice_Sslip,lattice_Sslip_v,lattice_Stwin,lattice_Stwin_v,lattice_maxNslipFamily,lattice_maxNtwinFamily, &
                    lattice_NslipSystem,lattice_NtwinSystem,lattice_shearTwin
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: g,ip,el
real(pReal), intent(in) :: Temperature
real(pReal), dimension(6), intent(in) :: Tstar_v
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(inout) :: state
real(pReal), dimension(3,3), intent(out) :: Lp
real(pReal), dimension(9,9), intent(out) :: dLp_dTstar
!* Local variables
integer(pInt) myInstance,myStructure,ns,nt,f,i,j,k,l,m,n,index_myFamily
real(pReal) sumf,StressRatio_p,StressRatio_pminus1,StressRatio_r,BoltzmannRatio,DotGamma0
real(pReal), dimension(3,3,3,3) :: dLp_dTstar3333
real(pReal), dimension(constitutive_dislotwin_totalNslip(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
   gdot_slip,dgdot_dtauslip,tau_slip
real(pReal), dimension(constitutive_dislotwin_totalNtwin(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
   gdot_twin,dgdot_dtautwin,tau_twin
real(pReal), dimension(6) :: gdot_sb,dgdot_dtausb,tau_sb
real(pReal), dimension(3,3) :: eigVectors, sb_Smatrix
real(pReal), dimension(3)   :: eigValues, sb_s, sb_m
real(pReal), dimension(3,6), parameter :: &
  sb_sComposition = &
    reshape(real([&
       1, 0, 1, &
       1, 0,-1, &
       1, 1, 0, &
       1,-1, 0, &
       0, 1, 1, &
       0, 1,-1  &
       ],pReal),[ 3,6]), &
  sb_mComposition = &
    reshape(real([&
       1, 0,-1, &
       1, 0,+1, &
       1,-1, 0, &
       1, 1, 0, &
       0, 1,-1, &
       0, 1, 1  &
       ],pReal),[ 3,6])
logical error

!* Shortened notation
myInstance  = phase_plasticityInstance(material_phase(g,ip,el))
myStructure = constitutive_dislotwin_structure(myInstance)
ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)

!* Total twin volume fraction
sumf = sum(state(g,ip,el)%p((2_pInt*ns+1_pInt):(2_pInt*ns+nt))) ! safe for nt == 0

Lp = 0.0_pReal
dLp_dTstar3333 = 0.0_pReal
dLp_dTstar = 0.0_pReal

!* Dislocation glide part
gdot_slip = 0.0_pReal
dgdot_dtauslip = 0.0_pReal
j = 0_pInt
do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
   index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
   do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
      j = j+1_pInt

      !* Calculation of Lp
      !* Resolved shear stress on slip system
      tau_slip(j) = dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))

      !* Stress ratios
      StressRatio_p = (abs(tau_slip(j))/state(g,ip,el)%p(5*ns+3*nt+j))**constitutive_dislotwin_p(myInstance)
      StressRatio_pminus1 = (abs(tau_slip(j))/state(g,ip,el)%p(5*ns+3*nt+j))**(constitutive_dislotwin_p(myInstance)-1.0_pReal)
      !* Boltzmann ratio
      BoltzmannRatio = constitutive_dislotwin_QedgePerSlipSystem(f,myInstance)/(kB*Temperature)
      !* Initial shear rates
      DotGamma0 = &
        state(g,ip,el)%p(j)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)*&
        constitutive_dislotwin_v0PerSlipSystem(f,myInstance)

      !* Shear rates due to slip
      gdot_slip(j) = DotGamma0*exp(-BoltzmannRatio*(1-StressRatio_p)**constitutive_dislotwin_q(myInstance))*&
                     sign(1.0_pReal,tau_slip(j))

      !* Derivatives of shear rates
      dgdot_dtauslip(j) = &
        ((abs(gdot_slip(j))*BoltzmannRatio*&
        constitutive_dislotwin_p(myInstance)*constitutive_dislotwin_q(myInstance))/state(g,ip,el)%p(5*ns+3*nt+j))*&
        StressRatio_pminus1*(1-StressRatio_p)**(constitutive_dislotwin_q(myInstance)-1.0_pReal)

      !* Plastic velocity gradient for dislocation glide
      Lp = Lp + (1.0_pReal - sumf)*gdot_slip(j)*lattice_Sslip(:,:,index_myFamily+i,myStructure)

      !* Calculation of the tangent of Lp
      forall (k=1_pInt:3_pInt,l=1_pInt:3_pInt,m=1_pInt:3_pInt,n=1_pInt:3_pInt) &
        dLp_dTstar3333(k,l,m,n) = &
        dLp_dTstar3333(k,l,m,n) + dgdot_dtauslip(j)*&
                                  lattice_Sslip(k,l,index_myFamily+i,myStructure)*&
                                  lattice_Sslip(m,n,index_myFamily+i,myStructure)
   enddo
enddo

!* Shear banding (shearband) part
if(constitutive_dislotwin_sbVelocity(myInstance) /= 0.0_pReal) then
  gdot_sb = 0.0_pReal
  dgdot_dtausb = 0.0_pReal
  call math_spectralDecompositionSym33(math_Mandel6to33(Tstar_v),eigValues,eigVectors, error)
  do j = 1_pInt,6_pInt
    sb_s = 0.5_pReal*sqrt(2.0_pReal)*math_mul33x3(eigVectors,sb_sComposition(1:3,j))
    sb_m = 0.5_pReal*sqrt(2.0_pReal)*math_mul33x3(eigVectors,sb_mComposition(1:3,j))
    sb_Smatrix = math_tensorproduct(sb_s,sb_m)
    constitutive_dislotwin_sbSv(1:6,j,g,ip,el) = math_Mandel33to6(math_symmetric33(sb_Smatrix))
  
    !* Calculation of Lp
    !* Resolved shear stress on shear banding system
    tau_sb(j) = dot_product(Tstar_v,constitutive_dislotwin_sbSv(1:6,j,g,ip,el))
  
    ! if (debug_selectiveDebugger .and. g==debug_g .and. ip==debug_i .and. el==debug_e) then
    !   write(6,'(a,3(i3,1x),a,i1,a,e10.3)') '### TAU SHEARBAND at g ip el ',g,ip,el,' on family ',j,' : ',tau
    ! endif
  
    !* Stress ratios
    StressRatio_p = (abs(tau_sb(j))/constitutive_dislotwin_sbResistance(myInstance))**constitutive_dislotwin_p(myInstance)
    StressRatio_pminus1 = (abs(tau_sb(j))/constitutive_dislotwin_sbResistance(myInstance))&
                                                                         **(constitutive_dislotwin_p(myInstance)-1.0_pReal)
    !* Boltzmann ratio
    BoltzmannRatio = constitutive_dislotwin_sbQedge(myInstance)/(kB*Temperature)
    !* Initial shear rates
    DotGamma0 = constitutive_dislotwin_sbVelocity(myInstance)

    !* Shear rates due to shearband
    gdot_sb(j) = DotGamma0*exp(-BoltzmannRatio*(1_pInt-StressRatio_p)**constitutive_dislotwin_q(myInstance))*&
                 sign(1.0_pReal,tau_sb(j))
                 
    !* Derivatives of shear rates
    dgdot_dtausb(j) = &
      ((abs(gdot_sb(j))*BoltzmannRatio*&
      constitutive_dislotwin_p(myInstance)*constitutive_dislotwin_q(myInstance))/constitutive_dislotwin_sbResistance(myInstance))*&
      StressRatio_pminus1*(1_pInt-StressRatio_p)**(constitutive_dislotwin_q(myInstance)-1.0_pReal)

    !* Plastic velocity gradient for shear banding
    Lp = Lp + gdot_sb(j)*sb_Smatrix

    !* Calculation of the tangent of Lp
    forall (k=1_pInt:3_pInt,l=1_pInt:3_pInt,m=1_pInt:3_pInt,n=1_pInt:3_pInt) &
      dLp_dTstar3333(k,l,m,n) = &
      dLp_dTstar3333(k,l,m,n) + dgdot_dtausb(j)*&
                                sb_Smatrix(k,l)*&
                                sb_Smatrix(m,n)
  enddo
end if

!* Mechanical twinning part
gdot_twin = 0.0_pReal
dgdot_dtautwin = 0.0_pReal
j = 0_pInt
do f = 1_pInt,lattice_maxNtwinFamily                                 ! loop over all slip families
   index_myFamily = sum(lattice_NtwinSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
   do i = 1_pInt,constitutive_dislotwin_Ntwin(f,myInstance)          ! process each (active) slip system in family
      j = j+1_pInt

      !* Calculation of Lp
      !* Resolved shear stress on twin system
      tau_twin(j) = dot_product(Tstar_v,lattice_Stwin_v(:,index_myFamily+i,myStructure))

      !* Stress ratios
      StressRatio_r = (state(g,ip,el)%p(6*ns+3*nt+j)/tau_twin(j))**constitutive_dislotwin_r(myInstance)

      !* Shear rates and their derivatives due to twin
      if ( tau_twin(j) > 0.0_pReal ) then
        gdot_twin(j) = &
          (constitutive_dislotwin_MaxTwinFraction(myInstance)-sumf)*lattice_shearTwin(index_myFamily+i,myStructure)*&
          state(g,ip,el)%p(6*ns+4*nt+j)*constitutive_dislotwin_Ndot0PerTwinSystem(f,myInstance)*exp(-StressRatio_r)
        dgdot_dtautwin(j) = ((gdot_twin(j)*constitutive_dislotwin_r(myInstance))/tau_twin(j))*StressRatio_r
      endif

      !* Plastic velocity gradient for mechanical twinning
      Lp = Lp + gdot_twin(j)*lattice_Stwin(:,:,index_myFamily+i,myStructure)

      !* Calculation of the tangent of Lp
      forall (k=1_pInt:3_pInt,l=1_pInt:3_pInt,m=1_pInt:3_pInt,n=1_pInt:3_pInt) &
        dLp_dTstar3333(k,l,m,n) = &
        dLp_dTstar3333(k,l,m,n) + dgdot_dtautwin(j)*&
                                  lattice_Stwin(k,l,index_myFamily+i,myStructure)*&
                                  lattice_Stwin(m,n,index_myFamily+i,myStructure)
   enddo
enddo

dLp_dTstar = math_Plain3333to99(dLp_dTstar3333)

!if ((ip==1).and.(el==1)) then
!   write(6,*) '#LP/TANGENT#'
!   write(6,*)
!   write(6,*) 'Tstar_v', Tstar_v
!   write(6,*) 'tau_slip', tau_slip
!   write(6,'(a10,/,4(3(e20.8,1x),/))') 'state',state(1,1,1)%p
!   write(6,'(a,/,3(3(f10.4,1x)/))') 'Lp',Lp
!   write(6,'(a,/,9(9(f10.4,1x)/))') 'dLp_dTstar',dLp_dTstar
!endif

end subroutine


function constitutive_dislotwin_dotState(Tstar_v,Temperature,state,g,ip,el)
!*********************************************************************
!* rate of change of microstructure                                  *
!* INPUT:                                                            *
!*  - Temperature     : temperature                                  *
!*  - state           : microstructure quantities                    *
!*  - Tstar_v         : 2nd Piola Kirchhoff stress tensor (Mandel)   *
!*  - ipc             : component-ID at current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!* OUTPUT:                                                           *
!*  - constitutive_dotState : evolution of state variable            *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec

use math,     only: pi
use mesh,     only: mesh_NcpElems, mesh_maxNips
use material, only: homogenization_maxNgrains, material_phase, phase_plasticityInstance
use lattice,  only: lattice_Sslip_v, lattice_Stwin_v, &
                    lattice_maxNslipFamily,lattice_maxNtwinFamily, &
                    lattice_NslipSystem,lattice_NtwinSystem
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: g,ip,el
real(pReal), intent(in) :: Temperature
real(pReal), dimension(6), intent(in) :: Tstar_v
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(in) :: state
real(pReal), dimension(constitutive_dislotwin_sizeDotState(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
constitutive_dislotwin_dotState
!* Local variables
integer(pInt) MyInstance,MyStructure,ns,nt,f,i,j,index_myFamily
real(pReal) sumf,StressRatio_p,StressRatio_pminus1,BoltzmannRatio,DotGamma0,&
            EdgeDipMinDistance,AtomicVolume,VacancyDiffusion,StressRatio_r
real(pReal), dimension(constitutive_dislotwin_totalNslip(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
gdot_slip,tau_slip,DotRhoMultiplication,EdgeDipDistance,DotRhoEdgeEdgeAnnihilation,DotRhoEdgeDipAnnihilation,&

ClimbVelocity,DotRhoEdgeDipClimb,DotRhoDipFormation
real(pReal), dimension(constitutive_dislotwin_totalNtwin(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
             tau_twin

!* Shortened notation
myInstance  = phase_plasticityInstance(material_phase(g,ip,el))
MyStructure = constitutive_dislotwin_structure(myInstance)
ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)

!* Total twin volume fraction
sumf = sum(state(g,ip,el)%p((2_pInt*ns+1_pInt):(2_pInt*ns+nt))) ! safe for nt == 0

constitutive_dislotwin_dotState = 0.0_pReal

!* Dislocation density evolution
gdot_slip = 0.0_pReal
j = 0_pInt
do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
   index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,MyStructure)) ! at which index starts my family
   do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
      j = j+1_pInt


      !* Resolved shear stress on slip system
      tau_slip(j) = dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))
      !* Stress ratios
      StressRatio_p = (abs(tau_slip(j))/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                               constitutive_dislotwin_p(myInstance)
      StressRatio_pminus1 = (abs(tau_slip(j))/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                   (constitutive_dislotwin_p(myInstance)-1.0_pReal)
      !* Boltzmann ratio
      BoltzmannRatio = constitutive_dislotwin_QedgePerSlipSystem(f,myInstance)/(kB*Temperature)
      !* Initial shear rates
      DotGamma0 = &
        state(g,ip,el)%p(j)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)*&
        constitutive_dislotwin_v0PerSlipSystem(f,myInstance)

      !* Shear rates due to slip
      gdot_slip(j) = DotGamma0*exp(-BoltzmannRatio*(1_pInt-StressRatio_p)**constitutive_dislotwin_q(myInstance))*&
                     sign(1.0_pReal,tau_slip(j))

      !* Multiplication
      DotRhoMultiplication(j) = abs(gdot_slip(j))/&
                                (constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)*state(g,ip,el)%p(4*ns+2*nt+j))

      !* Dipole formation
      EdgeDipMinDistance = &
        constitutive_dislotwin_CEdgeDipMinDistance(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)
      if (tau_slip(j) == 0.0_pReal) then
        DotRhoDipFormation(j) = 0.0_pReal
      else
        EdgeDipDistance(j) = &
          (3.0_pReal*constitutive_dislotwin_Gmod(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance))/&
          (16.0_pReal*pi*abs(tau_slip(j)))
      if (EdgeDipDistance(j)>state(g,ip,el)%p(4*ns+2*nt+j)) EdgeDipDistance(j)=state(g,ip,el)%p(4*ns+2*nt+j)
      if (EdgeDipDistance(j)<EdgeDipMinDistance) EdgeDipDistance(j)=EdgeDipMinDistance
        DotRhoDipFormation(j) = &
          ((2.0_pReal*EdgeDipDistance(j))/constitutive_dislotwin_burgersPerSlipSystem(f,myInstance))*&
          state(g,ip,el)%p(j)*abs(gdot_slip(j))
      endif

      !* Spontaneous annihilation of 2 single edge dislocations
      DotRhoEdgeEdgeAnnihilation(j) = &
        ((2.0_pReal*EdgeDipMinDistance)/constitutive_dislotwin_burgersPerSlipSystem(f,myInstance))*&
        state(g,ip,el)%p(j)*abs(gdot_slip(j))

      !* Spontaneous annihilation of a single edge dislocation with a dipole constituent
      DotRhoEdgeDipAnnihilation(j) = &
        ((2.0_pReal*EdgeDipMinDistance)/constitutive_dislotwin_burgersPerSlipSystem(f,myInstance))*&
        state(g,ip,el)%p(ns+j)*abs(gdot_slip(j))

      !* Dislocation dipole climb
      AtomicVolume = &
        constitutive_dislotwin_CAtomicVolume(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)**(3.0_pReal)
      VacancyDiffusion = &
        constitutive_dislotwin_D0(myInstance)*exp(-constitutive_dislotwin_Qsd(myInstance)/(kB*Temperature))
      if (tau_slip(j) == 0.0_pReal) then
        DotRhoEdgeDipClimb(j) = 0.0_pReal
      else
        ClimbVelocity(j) = &
          ((3.0_pReal*constitutive_dislotwin_Gmod(myInstance)*VacancyDiffusion*AtomicVolume)/(2.0_pReal*pi*kB*Temperature))*&
          (1/(EdgeDipDistance(j)+EdgeDipMinDistance))
        DotRhoEdgeDipClimb(j) = &
          (4.0_pReal*ClimbVelocity(j)*state(g,ip,el)%p(ns+j))/(EdgeDipDistance(j)-EdgeDipMinDistance)
      endif

      !* Edge dislocation density rate of change
      constitutive_dislotwin_dotState(j) = &
        DotRhoMultiplication(j)-DotRhoDipFormation(j)-DotRhoEdgeEdgeAnnihilation(j)

      !* Edge dislocation dipole density rate of change
      constitutive_dislotwin_dotState(ns+j) = &
        DotRhoDipFormation(j)-DotRhoEdgeDipAnnihilation(j)-DotRhoEdgeDipClimb(j)

   enddo
enddo

!* Twin volume fraction evolution
j = 0_pInt
do f = 1_pInt,lattice_maxNtwinFamily                                 ! loop over all twin families
   index_myFamily = sum(lattice_NtwinSystem(1:f-1_pInt,MyStructure)) ! at which index starts my family
   do i = 1_pInt,constitutive_dislotwin_Ntwin(f,myInstance)          ! process each (active) twin system in family
      j = j+1_pInt

      !* Resolved shear stress on twin system
      tau_twin(j) = dot_product(Tstar_v,lattice_Stwin_v(:,index_myFamily+i,myStructure))
      !* Stress ratios
      StressRatio_r = (state(g,ip,el)%p(6*ns+3*nt+j)/tau_twin(j))**constitutive_dislotwin_r(myInstance)

      !* Shear rates and their derivatives due to twin
      if ( tau_twin(j) > 0.0_pReal ) then
        constitutive_dislotwin_dotState(2_pInt*ns+j) = &
          (constitutive_dislotwin_MaxTwinFraction(myInstance)-sumf)*&
          state(g,ip,el)%p(6_pInt*ns+4_pInt*nt+j)*constitutive_dislotwin_Ndot0PerTwinSystem(f,myInstance)*exp(-StressRatio_r)
      endif

   enddo
enddo

!write(6,*) '#DOTSTATE#'
!write(6,*)
!write(6,'(a,/,4(3(f30.20,1x)/))') 'tau slip',tau_slip
!write(6,'(a,/,4(3(f30.20,1x)/))') 'gamma slip',gdot_slip
!write(6,'(a,/,4(3(f30.20,1x)/))') 'RhoEdge',state(g,ip,el)%p(1:ns)
!write(6,'(a,/,4(3(f30.20,1x)/))') 'Threshold Slip', state(g,ip,el)%p(5*ns+3*nt+1:6*ns+3*nt)
!write(6,'(a,/,4(3(f30.20,1x)/))') 'Multiplication',DotRhoMultiplication
!write(6,'(a,/,4(3(f30.20,1x)/))') 'DipFormation',DotRhoDipFormation
!write(6,'(a,/,4(3(f30.20,1x)/))') 'SingleSingle',DotRhoEdgeEdgeAnnihilation
!write(6,'(a,/,4(3(f30.20,1x)/))') 'SingleDipole',DotRhoEdgeDipAnnihilation
!write(6,'(a,/,4(3(f30.20,1x)/))') 'DipClimb',DotRhoEdgeDipClimb

end function


!*********************************************************************
!* (instantaneous) incremental change of microstructure              *
!*********************************************************************
function constitutive_dislotwin_deltaState(Tstar_v, Temperature, state, g,ip,el)

use prec,     only: pReal, &
                    pInt, &
                    p_vec
use mesh,     only: mesh_NcpElems, &
                    mesh_maxNips
use material, only: homogenization_maxNgrains, &
                    material_phase, &
                    phase_plasticityInstance

implicit none

!*** input variables
integer(pInt), intent(in) ::                g, &                      ! current grain number
                                            ip, &                     ! current integration point
                                            el                        ! current element number
real(pReal), intent(in) ::                  Temperature               ! temperature
real(pReal), dimension(6), intent(in) ::    Tstar_v                   ! current 2nd Piola-Kirchhoff stress in Mandel notation
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(in) :: &
                                            state                     ! current microstructural state

!*** output variables
real(pReal), dimension(constitutive_dislotwin_sizeDotState(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
                                            constitutive_dislotwin_deltaState ! change of state variables / microstructure
 
!*** local variables


constitutive_dislotwin_deltaState = 0.0_pReal
end function


pure function constitutive_dislotwin_dotTemperature(Tstar_v,Temperature,state,g,ip,el)
!*********************************************************************
!* rate of change of microstructure                                  *
!* INPUT:                                                            *
!*  - Temperature     : temperature                                  *
!*  - Tstar_v         : 2nd Piola Kirchhoff stress tensor (Mandel)   *
!*  - ipc             : component-ID at current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!* OUTPUT:                                                           *
!*  - constitutive_dotTemperature : evolution of Temperature         *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec
use mesh,     only: mesh_NcpElems,mesh_maxNips
use material, only: homogenization_maxNgrains
implicit none

!* Input-Output variables
integer(pInt), intent(in) :: g,ip,el
real(pReal), intent(in) :: Temperature
real(pReal), dimension(6), intent(in) :: Tstar_v
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(in) :: state
real(pReal) constitutive_dislotwin_dotTemperature

constitutive_dislotwin_dotTemperature = 0.0_pReal
end function


function constitutive_dislotwin_postResults(Tstar_v,Temperature,dt,state,g,ip,el)
!*********************************************************************
!* return array of constitutive results                              *
!* INPUT:                                                            *
!*  - Temperature     : temperature                                  *
!*  - Tstar_v         : 2nd Piola Kirchhoff stress tensor (Mandel)   *
!*  - dt              : current time increment                       *
!*  - ipc             : component-ID at current integration point    *
!*  - ip              : current integration point                    *
!*  - el              : current element                              *
!*********************************************************************
use prec,     only: pReal,pInt,p_vec
use math,     only: pi,math_Mandel6to33, math_spectralDecompositionSym33
use mesh,     only: mesh_NcpElems,mesh_maxNips
use material, only: homogenization_maxNgrains,material_phase,phase_plasticityInstance,phase_Noutput
use lattice,  only: lattice_Sslip_v,lattice_Stwin_v,lattice_maxNslipFamily,lattice_maxNtwinFamily, &
                    lattice_NslipSystem,lattice_NtwinSystem
implicit none

!* Definition of variables
integer(pInt), intent(in) :: g,ip,el
real(pReal), intent(in) :: dt,Temperature
real(pReal), dimension(6), intent(in) :: Tstar_v
type(p_vec), dimension(homogenization_maxNgrains,mesh_maxNips,mesh_NcpElems), intent(in) :: state
integer(pInt) myInstance,myStructure,ns,nt,f,o,i,c,j,index_myFamily
real(pReal) sumf,tau,StressRatio_p,StressRatio_pminus1,BoltzmannRatio,DotGamma0,StressRatio_r,gdot_slip,dgdot_dtauslip
real(pReal), dimension(3,3) :: eigVectors
real(pReal), dimension (3) :: eigValues
logical error
real(pReal), dimension(constitutive_dislotwin_sizePostResults(phase_plasticityInstance(material_phase(g,ip,el)))) :: &
constitutive_dislotwin_postResults

!* Shortened notation
myInstance  = phase_plasticityInstance(material_phase(g,ip,el))
myStructure = constitutive_dislotwin_structure(myInstance)
ns = constitutive_dislotwin_totalNslip(myInstance)
nt = constitutive_dislotwin_totalNtwin(myInstance)

!* Total twin volume fraction
sumf = sum(state(g,ip,el)%p((2*ns+1):(2*ns+nt))) ! safe for nt == 0

!* Required output
c = 0_pInt
constitutive_dislotwin_postResults = 0.0_pReal

!* Spectral decomposition of stress
call math_spectralDecompositionSym33(math_Mandel6to33(Tstar_v),eigValues,eigVectors, error)

do o = 1_pInt,phase_Noutput(material_phase(g,ip,el))
   select case(constitutive_dislotwin_output(o,myInstance))

     case ('edge_density')
       constitutive_dislotwin_postResults(c+1_pInt:c+ns) = state(g,ip,el)%p(1:ns)
       c = c + ns
     case ('dipole_density')
       constitutive_dislotwin_postResults(c+1_pInt:c+ns) = state(g,ip,el)%p(ns+1:2_pInt*ns)
       c = c + ns
     case ('shear_rate_slip')
       j = 0_pInt
       do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
          index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
          do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
             j = j + 1_pInt

             !* Resolved shear stress on slip system
             tau = dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))
             !* Stress ratios
             StressRatio_p = (abs(tau)/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                               constitutive_dislotwin_p(myInstance)
             StressRatio_pminus1 = (abs(tau)/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                   (constitutive_dislotwin_p(myInstance)-1.0_pReal)
             !* Boltzmann ratio
             BoltzmannRatio = constitutive_dislotwin_QedgePerSlipSystem(f,myInstance)/(kB*Temperature)
             !* Initial shear rates
             DotGamma0 = &
               state(g,ip,el)%p(j)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)* &
               constitutive_dislotwin_v0PerSlipSystem(f,myInstance)

             !* Shear rates due to slip
             constitutive_dislotwin_postResults(c+j) = &
               DotGamma0*exp(-BoltzmannRatio*(1_pInt-StressRatio_p)**&
                                          constitutive_dislotwin_q(myInstance))*sign(1.0_pReal,tau)
       enddo ; enddo
       c = c + ns
     case ('mfp_slip')
       constitutive_dislotwin_postResults(c+1_pInt:c+ns) =&
                               state(g,ip,el)%p((4_pInt*ns+2_pInt*nt+1_pInt):(5_pInt*ns+2_pInt*nt))
       c = c + ns
     case ('resolved_stress_slip')
       j = 0_pInt
       do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
          index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
          do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
             j = j + 1_pInt
             constitutive_dislotwin_postResults(c+j) =&
                               dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))
       enddo; enddo
       c = c + ns
     case ('threshold_stress_slip')
       constitutive_dislotwin_postResults(c+1_pInt:c+ns) = &
                               state(g,ip,el)%p((5_pInt*ns+3_pInt*nt+1_pInt):(6_pInt*ns+3_pInt*nt))
       c = c + ns
     case ('edge_dipole_distance')
       j = 0_pInt
       do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
          index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
          do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
             j = j + 1_pInt
             constitutive_dislotwin_postResults(c+j) = &
               (3.0_pReal*constitutive_dislotwin_Gmod(myInstance)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance))/&
               (16.0_pReal*pi*abs(dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))))
             constitutive_dislotwin_postResults(c+j) = min(constitutive_dislotwin_postResults(c+j),state(g,ip,el)%p(4*ns+2*nt+j))
!            constitutive_dislotwin_postResults(c+j) = max(constitutive_dislotwin_postResults(c+j),state(g,ip,el)%p(4*ns+2*nt+j))
       enddo; enddo
       c = c + ns
      case ('resolved_stress_shearband')
       do j = 1_pInt,6_pInt                                                ! loop over all shearband families
           constitutive_dislotwin_postResults(c+j) = dot_product(Tstar_v, constitutive_dislotwin_sbSv(1:6,j,g,ip,el))
       enddo
       c = c + 6_pInt
      case ('schmid_factor_shearband')
        constitutive_dislotwin_postResults(c+1_pInt:c+6_pInt) = constitutive_dislotwin_sbSv(1:6,j,g,ip,el)
       c = c + 6_pInt
      case ('shear_rate_shearband')
        do j = 1_pInt,6_pInt                                                ! loop over all shearband families
             !* Resolved shear stress on shearband system
             tau = dot_product(Tstar_v,constitutive_dislotwin_sbSv(1:6,j,g,ip,el))
             !* Stress ratios
             StressRatio_p = (abs(tau)/constitutive_dislotwin_sbResistance(myInstance))**constitutive_dislotwin_p(myInstance)
             StressRatio_pminus1 = (abs(tau)/constitutive_dislotwin_sbResistance(myInstance))&
                                                                           **(constitutive_dislotwin_p(myInstance)-1.0_pReal)
             !* Boltzmann ratio
             BoltzmannRatio = constitutive_dislotwin_sbQedge(myInstance)/(kB*Temperature)
             !* Initial shear rates
             DotGamma0 = constitutive_dislotwin_sbVelocity(myInstance)

             !* Shear rates due to slip
             constitutive_dislotwin_postResults(c+j) = &
         DotGamma0*exp(-BoltzmannRatio*(1_pInt-StressRatio_p)**constitutive_dislotwin_q(myInstance))*sign(1.0_pReal,tau)
        enddo 
       c = c + 6_pInt
     case ('twin_fraction')
       constitutive_dislotwin_postResults(c+1_pInt:c+nt) = state(g,ip,el)%p((2_pInt*ns+1_pInt):(2_pInt*ns+nt))
       c = c + nt
     case ('shear_rate_twin')
       if (nt > 0_pInt) then
         j = 0_pInt
         do f = 1_pInt,lattice_maxNtwinFamily                                 ! loop over all twin families
           index_myFamily = sum(lattice_NtwinSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
           do i = 1,constitutive_dislotwin_Ntwin(f,myInstance)          ! process each (active) twin system in family
             j = j + 1_pInt

             !* Resolved shear stress on twin system
             tau = dot_product(Tstar_v,lattice_Stwin_v(:,index_myFamily+i,myStructure))
             !* Stress ratios
             StressRatio_r = (state(g,ip,el)%p(6_pInt*ns+3_pInt*nt+j)/tau)**constitutive_dislotwin_r(myInstance)

             !* Shear rates and their derivatives due to twin
             if ( tau > 0.0_pReal ) then
               constitutive_dislotwin_postResults(c+j) = &
                 (constitutive_dislotwin_MaxTwinFraction(myInstance)-sumf)*&
                 state(g,ip,el)%p(6_pInt*ns+4_pInt*nt+j)*constitutive_dislotwin_Ndot0PerTwinSystem(f,myInstance)*exp(-StressRatio_r)
             endif

         enddo ; enddo
       endif
       c = c + nt
     case ('mfp_twin')
       constitutive_dislotwin_postResults(c+1_pInt:c+nt) = state(g,ip,el)%p((5_pInt*ns+2_pInt*nt+1_pInt):(5_pInt*ns+3_pInt*nt))
       c = c + nt
     case ('resolved_stress_twin')
       if (nt > 0_pInt) then
         j = 0_pInt
         do f = 1_pInt,lattice_maxNtwinFamily                                 ! loop over all slip families
           index_myFamily = sum(lattice_NtwinSystem(1:f-1_pInt,myStructure))  ! at which index starts my family
           do i = 1_pInt,constitutive_dislotwin_Ntwin(f,myInstance)           ! process each (active) slip system in family
             j = j + 1_pInt
             constitutive_dislotwin_postResults(c+j) = dot_product(Tstar_v,lattice_Stwin_v(:,index_myFamily+i,myStructure))
         enddo; enddo
       endif
       c = c + nt
     case ('threshold_stress_twin')
       constitutive_dislotwin_postResults(c+1_pInt:c+nt) = state(g,ip,el)%p((6_pInt*ns+3_pInt*nt+1_pInt):(6_pInt*ns+4_pInt*nt))
       c = c + nt
     case ('stress_exponent')
       j = 0_pInt
       do f = 1_pInt,lattice_maxNslipFamily                                 ! loop over all slip families
          index_myFamily = sum(lattice_NslipSystem(1:f-1_pInt,myStructure)) ! at which index starts my family
          do i = 1_pInt,constitutive_dislotwin_Nslip(f,myInstance)          ! process each (active) slip system in family
             j = j + 1_pInt

             !* Resolved shear stress on slip system
             tau = dot_product(Tstar_v,lattice_Sslip_v(:,index_myFamily+i,myStructure))
             !* Stress ratios
             StressRatio_p = (abs(tau)/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                               constitutive_dislotwin_p(myInstance)
             StressRatio_pminus1 = (abs(tau)/state(g,ip,el)%p(5_pInt*ns+3_pInt*nt+j))**&
                                                   (constitutive_dislotwin_p(myInstance)-1.0_pReal)
             !* Boltzmann ratio
             BoltzmannRatio = constitutive_dislotwin_QedgePerSlipSystem(f,myInstance)/(kB*Temperature)
             !* Initial shear rates
             DotGamma0 = &
               state(g,ip,el)%p(j)*constitutive_dislotwin_burgersPerSlipSystem(f,myInstance)* &
               constitutive_dislotwin_v0PerSlipSystem(f,myInstance)

             !* Shear rates due to slip
             gdot_slip = DotGamma0*exp(-BoltzmannRatio*(1_pInt-StressRatio_p)**&
                                          constitutive_dislotwin_q(myInstance))*sign(1.0_pReal,tau)

             !* Derivatives of shear rates
             dgdot_dtauslip = &
               ((abs(gdot_slip)*BoltzmannRatio*&
               constitutive_dislotwin_p(myInstance)*constitutive_dislotwin_q(myInstance))/state(g,ip,el)%p(5*ns+3*nt+j))*&
               StressRatio_pminus1*(1_pInt-StressRatio_p)**(constitutive_dislotwin_q(myInstance)-1.0_pReal)

             !* Stress exponent
             if (gdot_slip==0.0_pReal) then
               constitutive_dislotwin_postResults(c+j) = 0.0_pReal
             else
               constitutive_dislotwin_postResults(c+j) = (tau/gdot_slip)*dgdot_dtauslip
             endif
       enddo ; enddo
       c = c + ns
     case ('sb_eigenvalues')
       forall (j = 1_pInt:3_pInt) &
       constitutive_dislotwin_postResults(c+j) = eigValues(j)
       c = c + 3_pInt
     case ('sb_eigenvectors')
       constitutive_dislotwin_postResults(c+1_pInt:c+9_pInt) = reshape(eigVectors,(/9/))
       c = c + 9_pInt
   end select
enddo

end function

END MODULE