00009 {
00010    THD_3dim_dataset *dset_in , *dset_out ;
00011    int Lxx=-1 , Lyy=-1 , Lzz=-1 , Mode=FFT_ABS ;
00012    char *prefix = "FFT" ;
00013    int iarg ;
00014 
00015    if( argc < 2 || strcmp(argv[1],"-help") == 0 ){
00016      printf(
00017        "Usage: 3dFFT [options] dataset\n"
00018        "Does the FFT of the input dataset in 3 directions (x,y,z) and\n"
00019        "produces the output dataset.\n"
00020        "\n"
00021        "Options\n"
00022        "=======\n"
00023        " -abs       = Outputs the magnitude of the FFT [default]\n"
00024        " -phase     = Outputs the phase of the FFT (-PI..PI)\n"
00025        " -complex   = Outputs the complex FFT\n"
00026        " -Lx xx     = Use FFT of length 'xx' in the x-direction\n"
00027        " -Ly yy     = Use FFT of length 'yy' in the y-direction\n"
00028        " -Lz zz     = Use FFT of length 'zz' in the z-direction\n"
00029        "              * Set a length to 0 to skip\n"
00030        "                the FFT in that direction\n"
00031        " -prefix pp = Use 'pp' for the output dataset prefix.\n"
00032        "\n"
00033        "Notes\n"
00034        "=====\n"
00035        " * The program can only do FFT lengths that are factorable\n"
00036        "    into powers of 2, 3, and 5.\n"
00037        " * For -abs and -phase, the output dataset is in float format.\n"
00038      ) ;
00039      exit(0) ;
00040    }
00041 
00042    mainENTRY("3dFFT main") ; machdep() ;
00043 
00044    /*--- scan args ---*/
00045 
00046    iarg = 1 ;
00047 
00048    while( iarg < argc && argv[iarg][0] == '-' ){
00049 
00050      if( strcmp(argv[iarg],"-abs") == 0 ){
00051        Mode = FFT_ABS ; iarg++ ; continue ;
00052      }
00053      if( strcmp(argv[iarg],"-phase") == 0 ){
00054        Mode = FFT_PHASE ; iarg++ ; continue ;
00055      }
00056      if( strcmp(argv[iarg],"-complex") == 0 ){
00057        Mode = FFT_COMPLEX ; iarg++ ; continue ;
00058      }
00059 
00060      if( strlen(argv[iarg]) == 3 && strncmp(argv[iarg],"-L",2) == 0 ){
00061        int lll=-1 ; char *ept ;
00062        iarg++ ;
00063        if( iarg >= argc ){
00064          fprintf(stderr,"** ERROR: need an argument after %s\n",argv[iarg-1]) ;
00065          exit(1) ;
00066        }
00067        lll = strtol( argv[iarg] , &ept , 10 ) ;
00068        if( *ept != '\0' ){
00069          fprintf(stderr,"** ERROR: bad argument after %s\n",argv[iarg-1]) ;
00070          exit(1) ;
00071        }
00072        switch( argv[iarg-1][2] ){
00073          case 'x': Lxx = lll ; break ;
00074          case 'y': Lyy = lll ; break ;
00075          case 'z': Lzz = lll ; break ;
00076          default:
00077            fprintf(stderr,"** ERROR: unknown option '%s'\n",argv[iarg-1]) ;
00078            exit(1) ;
00079        }
00080        iarg++ ; continue ;
00081      }
00082 
00083      if( strcmp(argv[iarg],"-prefix") == 0 ){
00084        iarg++ ;
00085        if( iarg >= argc ){
00086          fprintf(stderr,"** ERROR: need an argument after %s\n",argv[iarg-1]) ;
00087          exit(1) ;
00088        }
00089        prefix = strdup( argv[iarg] ) ;
00090        if( !THD_filename_ok(prefix) ){
00091          fprintf(stderr,"** ERROR: bad argument after %s\n",argv[iarg-1]) ;
00092          exit(1) ;
00093        }
00094        iarg++ ; continue ;
00095      }
00096 
00097      fprintf(stderr,"** ERROR: unknown option '%s'\n",argv[iarg]) ;
00098      exit(1) ;
00099    }
00100 
00101    if( iarg >= argc ){
00102      fprintf(stderr,"** ERROR: no input dataset on command line?!\n") ;
00103      exit(1) ;
00104    }
00105    if( Lxx == 0 && Lyy == 0 && Lzz == 0 ){
00106      fprintf(stderr,"** ERROR: -Lx, -Ly, -Lz all given as zero?!\n") ;
00107      exit(1) ;
00108    }
00109 
00110    /* open input dataset */
00111 
00112    dset_in = THD_open_dataset( argv[iarg] ) ;
00113    if( dset_in == NULL ){
00114      fprintf(stderr,"** ERROR: can't open dataset %s\n",argv[iarg]) ;
00115      exit(1) ;
00116    }
00117 }