29 lines
575 B
C
29 lines
575 B
C
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#include "nrutil.h"
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void spread(y,yy,n,x,m)
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float x,y,yy[];
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int m;
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unsigned long n;
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{
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int ihi,ilo,ix,j,nden;
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static long nfac[11]={0,1,1,2,6,24,120,720,5040,40320,362880};
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float fac;
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if (m > 10) nrerror("factorial table too small in spread");
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ix=(int)x;
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if (x == (float)ix) yy[ix] += y;
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else {
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ilo=LMIN(LMAX((long)(x-0.5*m+1.0),1),n-m+1);
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ihi=ilo+m-1;
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nden=nfac[m];
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fac=x-ilo;
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for (j=ilo+1;j<=ihi;j++) fac *= (x-j);
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yy[ihi] += y*fac/(nden*(x-ihi));
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for (j=ihi-1;j>=ilo;j--) {
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nden=(nden/(j+1-ilo))*(j-ihi);
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yy[j] += y*fac/(nden*(x-j));
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}
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}
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}
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