!--------------------------------------------------------------------------------------------------
! $Id$
!--------------------------------------------------------------------------------------------------
!> @author   Franz Roters, Max-Planck-Institut für Eisenforschung GmbH
!> @author   Philip Eisenlohr, Max-Planck-Institut für Eisenforschung GmbH
!> @author   Christoph Kords, Max-Planck-Institut für Eisenforschung GmbH
!> @author   Martin Diehl, Max-Planck-Institut für Eisenforschung GmbH
!> @author   Luv Sharma, Max-Planck-Institut für Eisenforschung GmbH
!> @brief    setting precision for real and int type depending on makros "FLOAT" and "INT"
!> @details  setting precision for real and int type and for DAMASK_NaN. Definition is made 
!!           depending on makros "FLOAT" and "INT" defined during compilation
!--------------------------------------------------------------------------------------------------

module prec

 implicit none
 private 
#if (FLOAT==4)
#ifdef Spectral
 SPECTRAL SOLVER DOES NOT SUPPORT SINGLE PRECISION, STOPPING COMPILATION
#endif
 integer,     parameter, public :: pReal = 4                                                        !< floating point single precition (was selected_real_kind(6,37), number with 6 significant digits, up to 1e+-37)
#ifdef __INTEL_COMPILER
 real(pReal), parameter, public :: DAMASK_NaN = Z'7F800001'                                         !< quiet NaN for single precision (from http://www.hpc.unimelb.edu.au/doc/f90lrm/dfum_035.html, copy can be found in documentation/Code/Fortran)
#endif
#ifdef __GFORTRAN__
 real(pReal), parameter, public :: DAMASK_NaN = real(Z'7F800001', pReal)                            !< quiet NaN for single precision (from http://www.hpc.unimelb.edu.au/doc/f90lrm/dfum_035.html, copy can be found in documentation/Code/Fortran)
#endif
#elif (FLOAT==8)
 integer,     parameter, public :: pReal = 8                                                        !< floating point double precision (was selected_real_kind(15,300), number with 15 significant digits, up to 1e+-300)
#ifdef __INTEL_COMPILER
 real(pReal), parameter, public :: DAMASK_NaN = Z'7FF8000000000000'                                 !< quiet NaN for double precision (from http://www.hpc.unimelb.edu.au/doc/f90lrm/dfum_035.html, copy can be found in documentation/Code/Fortran)
#endif
#ifdef __GFORTRAN__
 real(pReal), parameter, public :: DAMASK_NaN = real(Z'7FF8000000000000', pReal)                    !< quiet NaN for double precision (from http://www.hpc.unimelb.edu.au/doc/f90lrm/dfum_035.html, copy can be found in documentation/Code/Fortran)
#endif
#else
 NO SUITABLE PRECISION FOR REAL SELECTED, STOPPING COMPILATION
#endif

#if (INT==4)
 integer,     parameter, public :: pInt  = 4                                                        !< integer representation 32 bit (was selected_int_kind(9), number with at least up to +- 1e9)
#elif (INT==8)
 integer,     parameter, public :: pInt  = 8                                                        !< integer representation 64 bit (was selected_int_kind(12), number with at least up to +- 1e12)
#else
 NO SUITABLE PRECISION FOR INTEGER SELECTED, STOPPING COMPILATION
#endif

 integer,     parameter, public :: pLongInt  = 8                                                    !< integer representation 64 bit (was selected_int_kind(12), number with at least up to +- 1e12)
 real(pReal), parameter, public :: tol_math_check = 1.0e-8_pReal                                    !< tolerance for internal math self-checks (rotation)

 type, public :: p_vec                                                                              !< variable length datatype used for storage of state
   real(pReal), dimension(:), pointer :: p
 end type p_vec

 type, public :: p_intvec
   integer(pInt), dimension(:), pointer :: p
 end type p_intvec

#ifdef NEWSTATE
!http://stackoverflow.com/questions/3948210/can-i-have-a-pointer-to-an-item-in-an-allocatable-array
 type, public :: tState
   real(pReal), pointer, dimension(:,:) :: state, &                                                     ! material points, state size
                                           dotState, &
                                           state0, &
                                           partionedState0, &
                                           subState0, &
                                           state_backup, &
                                           deltaState, &
                                           previousDotState, &
                                           previousDotState2, &
                                           dotState_backup, &
                                           RK4dotState, &
                                           aTolState, &
                                           RKCK45dotState
 end type
#endif


 public :: &
   prec_init
 
contains

!--------------------------------------------------------------------------------------------------
!> @brief reporting precision and checking if DAMASK_NaN is set correctly
!--------------------------------------------------------------------------------------------------
subroutine prec_init
 use, intrinsic :: iso_fortran_env                                                                  ! to get compiler_version and compiler_options (at least for gfortran 4.6 at the moment)
 
 implicit none
 external :: &
   quit
   
 write(6,'(/,a)') ' <<<+-  prec init  -+>>>'
 write(6,'(a)') ' $Id$'
#include "compilation_info.f90"
#ifdef NEWSTATE
 write(6,'(a)')       'Using new state structure'
#endif
 write(6,'(a,i3)')    ' Bytes for pReal:    ',pReal
 write(6,'(a,i3)')    ' Bytes for pInt:     ',pInt
 write(6,'(a,i3)')    ' Bytes for pLongInt: ',pLongInt
 write(6,'(a,e10.3)') ' NaN:           ',     DAMASK_NaN
 write(6,'(a,l3,/)')  ' NaN /= NaN:         ',DAMASK_NaN/=DAMASK_NaN

 if (DAMASK_NaN == DAMASK_NaN) call quit(9000)

end subroutine prec_init

end module prec