mirror of
https://bitbucket.org/cosmicvoids/vide_public.git
synced 2025-07-04 15:21:11 +00:00
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
#include <math.h>
|
|
#define NRANSI
|
|
#include "nrutil.h"
|
|
#define NMAX 5000
|
|
#define GET_PSUM \
|
|
for (j=1;j<=ndim;j++) {\
|
|
for (sum=0.0,i=1;i<=mpts;i++) sum += p[i][j];\
|
|
psum[j]=sum;}
|
|
#define SWAP(a,b) {swap=(a);(a)=(b);(b)=swap;}
|
|
|
|
void amoeba(double **p, double y[], int ndim, double ftol,
|
|
double (*funk)(double []), int *nfunk)
|
|
{
|
|
double amotry(double **p, double y[], double psum[], int ndim,
|
|
double (*funk)(double []), int ihi, double fac);
|
|
int i,ihi,ilo,inhi,j,mpts=ndim+1;
|
|
double rtol,sum,swap,ysave,ytry,*psum;
|
|
|
|
psum=dvector(1,ndim);
|
|
*nfunk=0;
|
|
GET_PSUM
|
|
for (;;) {
|
|
ilo=1;
|
|
ihi = y[1]>y[2] ? (inhi=2,1) : (inhi=1,2);
|
|
for (i=1;i<=mpts;i++) {
|
|
if (y[i] <= y[ilo]) ilo=i;
|
|
if (y[i] > y[ihi]) {
|
|
inhi=ihi;
|
|
ihi=i;
|
|
} else if (y[i] > y[inhi] && i != ihi) inhi=i;
|
|
}
|
|
rtol=2.0*fabs(y[ihi]-y[ilo])/(fabs(y[ihi])+fabs(y[ilo]));
|
|
if (rtol < ftol) {
|
|
SWAP(y[1],y[ilo])
|
|
for (i=1;i<=ndim;i++) SWAP(p[1][i],p[ilo][i])
|
|
break;
|
|
}
|
|
if (*nfunk >= NMAX) nrerror("NMAX exceeded");
|
|
*nfunk += 2;
|
|
ytry=amotry(p,y,psum,ndim,funk,ihi,-1.0);
|
|
if (ytry <= y[ilo])
|
|
ytry=amotry(p,y,psum,ndim,funk,ihi,2.0);
|
|
else if (ytry >= y[inhi]) {
|
|
ysave=y[ihi];
|
|
ytry=amotry(p,y,psum,ndim,funk,ihi,0.5);
|
|
if (ytry >= ysave) {
|
|
for (i=1;i<=mpts;i++) {
|
|
if (i != ilo) {
|
|
for (j=1;j<=ndim;j++)
|
|
p[i][j]=psum[j]=0.5*(p[i][j]+p[ilo][j]);
|
|
y[i]=(*funk)(psum);
|
|
}
|
|
}
|
|
*nfunk += ndim;
|
|
GET_PSUM
|
|
}
|
|
} else --(*nfunk);
|
|
}
|
|
free_dvector(psum,1,ndim);
|
|
}
|
|
#undef SWAP
|
|
#undef GET_PSUM
|
|
#undef NMAX
|
|
#undef NRANSI
|