59 lines
1.4 KiB
C
59 lines
1.4 KiB
C
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/* Driver for routine fourn */
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#include <stdio.h>
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#define NRANSI
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#include "nr.h"
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#include "nrutil.h"
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#define NDIM 3
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#define NDAT2 1024
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int main(void)
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{
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int isign;
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long idum=(-23);
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unsigned long i,j,k,l,ndum=2,*nn;
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float *data1,*data2;
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nn=lvector(1,NDIM);
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data1=vector(1,NDAT2);
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data2=vector(1,NDAT2);
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for (i=1;i<=NDIM;i++) nn[i]=(ndum <<= 1);
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for (i=1;i<=nn[3];i++)
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for (j=1;j<=nn[2];j++)
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for (k=1;k<=nn[1];k++) {
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l=k+(j-1)*nn[1]+(i-1)*nn[2]*nn[1];
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l=(l<<1)-1;
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/* real part of component */
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data2[l]=data1[l]=2*ran1(&idum)-1;
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/* imaginary part of component */
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l++;
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data2[l]=data1[l]=2*ran1(&idum)-1;
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}
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isign=1;
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fourn(data2,nn,NDIM,isign);
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/* here would be any processing to be done in Fourier space */
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isign = -1;
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fourn(data2,nn,NDIM,isign);
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printf("Double 3-dimensional transform\n\n");
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printf("%22s %24s %20s\n",
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"Double transf.","Original data","Ratio");
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printf("%10s %13s %12s %13s %11s %13s\n\n",
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"real","imag.","real","imag.","real","imag.");
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for (i=1;i<=4;i++) {
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k=2*(j=2*i);
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l=k+(j-1)*nn[1]+(i-1)*nn[2]*nn[1];
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l=(l<<1)-1;
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printf("%12.2f %12.2f %10.2f %12.2f %14.2f %12.2f\n",
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data2[l],data2[l+1],data1[l],data1[l+1],
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data2[l]/data1[l],data2[l+1]/data1[l+1]);
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}
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printf("\nThe product of transform lengths is: %4lu\n",nn[1]*nn[2]*nn[3]);
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free_vector(data2,1,NDAT2);
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free_vector(data1,1,NDAT2);
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free_lvector(nn,1,NDIM);
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return 0;
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}
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#undef NRANSI
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