48 lines
734 B
C
48 lines
734 B
C
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#include "nrutil.h"
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#define MF 4
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#define BI (1.0/256)
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void mpinv(u,v,n,m)
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int m,n;
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unsigned char u[],v[];
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{
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void mpmov(),mpmul(),mpneg();
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unsigned char *rr,*s;
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int i,j,maxmn,mm;
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float fu,fv;
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maxmn=IMAX(n,m);
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rr=cvector(1,1+(maxmn<<1));
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s=cvector(1,maxmn);
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mm=IMIN(MF,m);
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fv=(float) v[mm];
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for (j=mm-1;j>=1;j--) {
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fv *= BI;
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fv += v[j];
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}
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fu=1.0/fv;
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for (j=1;j<=n;j++) {
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i=(int) fu;
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u[j]=(unsigned char) i;
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fu=256.0*(fu-i);
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}
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for (;;) {
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mpmul(rr,u,v,n,m);
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mpmov(s,&rr[1],n);
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mpneg(s,n);
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s[1] -= 254;
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mpmul(rr,s,u,n,n);
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mpmov(u,&rr[1],n);
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for (j=2;j<n;j++)
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if (s[j]) break;
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if (j==n) {
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free_cvector(s,1,maxmn);
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free_cvector(rr,1,1+(maxmn<<1));
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return;
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}
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}
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}
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#undef MF
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#undef BI
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