52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
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/* Driver for routine frprmn */
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#include <stdio.h>
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#include <math.h>
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#define NRANSI
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#include "nr.h"
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#include "nrutil.h"
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#define NDIM 3
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#define FTOL 1.0e-6
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#define PIO2 1.5707963
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float func(float x[])
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{
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return 1.0-bessj0(x[1]-0.5)*bessj0(x[2]-0.5)*bessj0(x[3]-0.5);
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}
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void dfunc(float x[],float df[])
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{
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df[1]=bessj1(x[1]-0.5)*bessj0(x[2]-0.5)*bessj0(x[3]-0.5);
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df[2]=bessj0(x[1]-0.5)*bessj1(x[2]-0.5)*bessj0(x[3]-0.5);
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df[3]=bessj0(x[1]-0.5)*bessj0(x[2]-0.5)*bessj1(x[3]-0.5);
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}
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int main(void)
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{
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int iter,k;
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float angl,fret,*p;
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p=vector(1,NDIM);
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printf("Program finds the minimum of a function\n");
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printf("with different trial starting vectors.\n");
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printf("True minimum is (0.5,0.5,0.5)\n");
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for (k=0;k<=4;k++) {
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angl=PIO2*k/4.0;
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p[1]=2.0*cos(angl);
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p[2]=2.0*sin(angl);
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p[3]=0.0;
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printf("\nStarting vector: (%6.4f,%6.4f,%6.4f)\n",
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p[1],p[2],p[3]);
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frprmn(p,NDIM,FTOL,&iter,&fret,func,dfunc);
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printf("Iterations: %3d\n",iter);
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printf("Solution vector: (%6.4f,%6.4f,%6.4f)\n",
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p[1],p[2],p[3]);
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printf("Func. value at solution %14f\n",fret);
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}
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free_vector(p,1,NDIM);
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return 0;
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}
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#undef NRANSI
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