88 lines
1.8 KiB
C
88 lines
1.8 KiB
C
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#include <math.h>
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#define NRANSI
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#include "nrutil.h"
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#define GET_PSUM \
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for (n=1;n<=ndim;n++) {\
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for (sum=0.0,m=1;m<=mpts;m++) sum += p[m][n];\
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psum[n]=sum;}
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extern long idum;
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float tt;
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void amebsa(float **p, float y[], int ndim, float pb[], float *yb, float ftol,
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float (*funk)(float []), int *iter, float temptr)
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{
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float amotsa(float **p, float y[], float psum[], int ndim, float pb[],
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float *yb, float (*funk)(float []), int ihi, float *yhi, float fac);
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float ran1(long *idum);
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int i,ihi,ilo,j,m,n,mpts=ndim+1;
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float rtol,sum,swap,yhi,ylo,ynhi,ysave,yt,ytry,*psum;
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psum=vector(1,ndim);
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tt = -temptr;
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GET_PSUM
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for (;;) {
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ilo=1;
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ihi=2;
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ynhi=ylo=y[1]+tt*log(ran1(&idum));
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yhi=y[2]+tt*log(ran1(&idum));
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if (ylo > yhi) {
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ihi=1;
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ilo=2;
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ynhi=yhi;
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yhi=ylo;
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ylo=ynhi;
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}
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for (i=3;i<=mpts;i++) {
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yt=y[i]+tt*log(ran1(&idum));
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if (yt <= ylo) {
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ilo=i;
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ylo=yt;
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}
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if (yt > yhi) {
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ynhi=yhi;
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ihi=i;
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yhi=yt;
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} else if (yt > ynhi) {
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ynhi=yt;
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}
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}
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rtol=2.0*fabs(yhi-ylo)/(fabs(yhi)+fabs(ylo));
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if (rtol < ftol || *iter < 0) {
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swap=y[1];
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y[1]=y[ilo];
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y[ilo]=swap;
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for (n=1;n<=ndim;n++) {
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swap=p[1][n];
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p[1][n]=p[ilo][n];
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p[ilo][n]=swap;
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}
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break;
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}
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*iter -= 2;
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ytry=amotsa(p,y,psum,ndim,pb,yb,funk,ihi,&yhi,-1.0);
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if (ytry <= ylo) {
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ytry=amotsa(p,y,psum,ndim,pb,yb,funk,ihi,&yhi,2.0);
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} else if (ytry >= ynhi) {
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ysave=yhi;
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ytry=amotsa(p,y,psum,ndim,pb,yb,funk,ihi,&yhi,0.5);
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if (ytry >= ysave) {
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for (i=1;i<=mpts;i++) {
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if (i != ilo) {
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for (j=1;j<=ndim;j++) {
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psum[j]=0.5*(p[i][j]+p[ilo][j]);
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p[i][j]=psum[j];
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}
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y[i]=(*funk)(psum);
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}
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}
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*iter -= ndim;
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GET_PSUM
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}
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} else ++(*iter);
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}
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free_vector(psum,1,ndim);
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}
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#undef GET_PSUM
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#undef NRANSI
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