41 lines
960 B
C
41 lines
960 B
C
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#include <math.h>
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#include "nrutil.h"
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void savgol(c,np,nl,nr,ld,m)
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float c[];
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int ld,m,nl,np,nr;
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{
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void lubksb(),ludcmp();
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int imj,ipj,j,k,kk,mm,*indx;
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float d,fac,sum,**a,*b;
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if (np < nl+nr+1 || nl < 0 || nr < 0 || ld > m || nl+nr < m)
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nrerror("bad args in savgol");
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indx=ivector(1,m+1);
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a=matrix(1,m+1,1,m+1);
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b=vector(1,m+1);
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for (ipj=0;ipj<=(m << 1);ipj++) {
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sum=(ipj ? 0.0 : 1.0);
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for (k=1;k<=nr;k++) sum += pow((double)k,(double)ipj);
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for (k=1;k<=nl;k++) sum += pow((double)-k,(double)ipj);
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mm=IMIN(ipj,2*m-ipj);
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for (imj = -mm;imj<=mm;imj+=2) a[1+(ipj+imj)/2][1+(ipj-imj)/2]=sum;
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}
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ludcmp(a,m+1,indx,&d);
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for (j=1;j<=m+1;j++) b[j]=0.0;
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b[ld+1]=1.0;
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lubksb(a,m+1,indx,b);
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for (kk=1;kk<=np;kk++) c[kk]=0.0;
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for (k = -nl;k<=nr;k++) {
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sum=b[1];
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fac=1.0;
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for (mm=1;mm<=m;mm++) sum += b[mm+1]*(fac *= k);
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kk=((np-k) % np)+1;
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c[kk]=sum;
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}
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free_vector(b,1,m+1);
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free_matrix(a,1,m+1,1,m+1);
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free_ivector(indx,1,m+1);
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}
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