[gmx-developers] Current status FFTW-3D

[Roland Schulz]

I would like to test first the FFT with the timefft test program. I did some 
changes so that it compiles (see below) - the test program was not up to date 
to the rest of the CVS. But now the test program crashes most probably 
because of a memory error. Since it is more difficult to debug someone else 
code, has someone an idea, what the problem is?


On Friday 31 August 2007 11:10, Erik Lindahl wrote:
> On Aug 31, 2007, at 4:04 PM, Roland Schulz wrote:

> It is indeed only the first dimension that is real-to-complex, but
> since the resulting data then only contains half as many points we
> will cut the execution time in the remaining dimensions by 50% too.
you're right

[license discussion]
ok I see

Roland


RCS file: /home/gmx/cvs/gmx/src/mdlib/timefft.c,v
retrieving revision 1.9
diff -u -r1.9 timefft.c
--- timefft.c   19 Apr 2006 09:05:15 -0000      1.9
+++ timefft.c   31 Aug 2007 19:35:40 -0000
@@ -46,6 +46,8 @@
 #include "mdrun.h"
 #include "main.h"
 #include "statutil.h"
+#include "fftgrid.h"
+#include "fftw3.h"

 #ifdef GMX_MPI
 #include "gmx_parallel_3dfft.h"
@@ -88,7 +90,7 @@
   parse_common_args(&argc,argv,
                    PCA_CAN_SET_DEFFNM | (MASTER(cr) ? 0 : PCA_QUIET),
                    NFILE,fnm,asize(pa),pa,0,NULL,0,NULL);
-  open_log(ftp2fn(efLOG,NFILE,fnm),cr);
+ open_log(ftp2fn(efLOG,NFILE,fnm),cr,FALSE);

   snew(niter,NNN);
   snew(ct,NNN);
@@ -110,16 +112,16 @@
     if (MASTER(cr))
       fprintf(stderr,"\r3D FFT (%s precision) %3d^3, niter %3d     ",
              (rsize == 8) ? "Double" : "Single",n,nit);
-
-    g  = mk_fftgrid(stdlog,(nnode > 1),n,n,n,bOptFFT);
+
+    g  = mk_fftgrid(n,n,n,NULL,cr);

     if (PAR(cr))
       start = time(NULL);
     else
       start_time();
     for(j=0; (j<nit); j++) {
-      gmxfft3D(g,FFTW_FORWARD,cr);
-      gmxfft3D(g,FFTW_BACKWARD,cr);
+      gmxfft3D(g,GMX_FFT_REAL_TO_COMPLEX,cr);
+      gmxfft3D(g,GMX_FFT_COMPLEX_TO_REAL,cr);
     }
     if (PAR(cr))
       rt[i] = time(NULL)-start;