55 lines
1.1 KiB
C
55 lines
1.1 KiB
C
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/* Driver for routine convlv */
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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 N 16 /* data array size */
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#define M 9 /* response function dimension - must be odd */
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#define N2 (2*N)
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int main(void)
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{
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unsigned long i,j;
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int isign;
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float cmp,*data,*respns,*resp,*ans;
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data=vector(1,N);
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respns=vector(1,N);
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resp=vector(1,N);
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ans=vector(1,N2);
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for (i=1;i<=N;i++)
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if ((i >= N/2-N/8) && (i <= N/2+N/8))
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data[i]=1.0;
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else
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data[i]=0.0;
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for (i=1;i<=M;i++) {
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if ((i > 2) && (i < 7))
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respns[i]=1.0;
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else
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respns[i]=0.0;
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resp[i]=respns[i];
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}
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isign=1;
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convlv(data,N,resp,M,isign,ans);
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/* compare with a direct convolution */
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printf("%3s %14s %13s\n","i","CONVLV","Expected");
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for (i=1;i<=N;i++) {
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cmp=0.0;
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for (j=1;j<=M/2;j++) {
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cmp += data[((i-j-1+N) % N)+1]*respns[j+1];
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cmp += data[((i+j-1) % N)+1]*respns[M-j+1];
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}
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cmp += data[i]*respns[1];
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printf("%3ld %15.6f %12.6f\n",i,ans[i],cmp);
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}
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free_vector(ans,1,N2);
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free_vector(resp,1,N);
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free_vector(respns,1,N);
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free_vector(data,1,N);
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return 0;
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}
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#undef NRANSI
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