! 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 prec
!##############################################################

implicit none
 
!    *** Precision of real and integer variables ***
integer, parameter, public :: pReal = selected_real_kind(6,37)       ! 6 significant digits, up to 1e+-37
integer, parameter, public :: pInt  = selected_int_kind(9)           ! up to +- 1e9
integer, parameter, public :: pLongInt  = 4                          ! should be 64bit
real(pReal), parameter, public :: tol_math_check = 1.0e-5_pReal
real(pReal), parameter, public :: tol_gravityNodePos = 1.0e-36_pReal

! NaN is precision dependent 
! from http://www.hpc.unimelb.edu.au/doc/f90lrm/dfum_035.html
! copy can be found in documentation/Code/Fortran
#ifdef __INTEL_COMPILER
#if __INTEL_COMPILER<12000
  real(pReal), parameter, public :: DAMASK_NaN = Z'Z'7F800001', pReal'
#else
  real(pReal), parameter, public :: DAMASK_NaN = real(Z'7F800001', pReal)
#endif
#else
real(pReal), parameter, public :: DAMASK_NaN = real(Z'7F800001', pReal)
#endif
type :: p_vec
  real(pReal), dimension(:), pointer :: p
end type p_vec

CONTAINS

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

!$OMP CRITICAL (write2out)
  write(6,*)
  write(6,*) '<<<+-  prec_single init  -+>>>'
  write(6,*) '$Id$'
#include "compilation_info.f90"
  write(6,'(a,i3)')   ' Bytes for pReal:    ',pReal
  write(6,'(a,i3)')   ' Bytes for pInt:     ',pInt
  write(6,'(a,i3)')   ' Bytes for pLongInt: ',pLongInt
  write(6,'(a,e10.3)') ' NaN:         ',DAMASK_NAN
  write(6,'(a,l3)')   ' NaN /= NaN:         ',DAMASK_NaN/=DAMASK_NaN
  if (DAMASK_NaN == DAMASK_NaN) call quit(9000)
  write(6,*)
!$OMP END CRITICAL (write2out)

end subroutine

END MODULE prec