added set_timelimit functionality to fortran-wrapper of FFTW and introcudec it to DAMASK_spectral.f90

code/DAMASK_spectral.f90

@@ -424,7 +424,7 @@ program DAMASK_spectral
      call dfftw_plan_with_nthreads(DAMASK_NumThreadsInt) 
    endif
 #endif
- !call dfftw_timelimit(fftw_timelimit)                          ! is not working, have to fix it in FFTW source file
+ call dfftw_set_timelimit(fftw_timelimit)                          ! is not working, have to fix it in FFTW source file
  select case(IO_lc(fftw_planner_flag))                          ! setting parameters for the plan creation of FFTW. Basically a translation from fftw3.f
    case('estimate','fftw_estimate')                             ! ordered from slow execution (but fast plan creation) to fast execution
      fftw_flag = 64

code/makefile

@@ -6,8 +6,16 @@
 # Uses OpenMP to parallelise the material subroutines (set number of cores with "export DAMASK_NUM_THREADS=n" to n)
 # Uses linux threads to parallelise fftw3
 # Besides of the f90 files written at MPIE, the two library files of fftw3 "libfftw3_threads.a" "libfftw3.a" are also needed
-# Install fftw3 (v3.3 is tested) with "./configure --enable-threads --enable-sse2 --enable-shared" and "make"; "make install" is not needed
-# as long as the two library files "libfftw3_threads.a" "libfftw3.a" are copied to the /../lib directory.
+# Install fftw3 (v3.3 is tested):
+# -Apply the following patch to api/f77funcs.h, line 92 in the FFTW source:
+#
+#  FFTW_VOIDFUNC F77(set_timelimit,SET_TIMELIMIT)(double *t)
+#  {
+#      X(set_timelimit)(*t);
+#  }
+# -Do "./configure --enable-threads --enable-sse2 --enable-shared" and "make"; "make install" is not needed
+#  as long as the two library files "libfftw3_threads.a" "libfftw3.a" are copied to the /../lib directory.
+# for single precision also use --enable-float
 # Need the AMD Core Math Library to be installed (v 4.4 is tested)
 ########################################################################################
 # OPTIONS = standard (alternative): meaning