41 lines
682 B
C
41 lines
682 B
C
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#include "nrutil.h"
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float **y,*xx;
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void rkdumb(vstart,nvar,x1,x2,nstep,derivs)
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float vstart[],x1,x2;
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int nstep,nvar;
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void (*derivs)();
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{
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void rk4();
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int i,k;
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float x,h;
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float *v,*vout,*dv;
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v=vector(1,nvar);
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vout=vector(1,nvar);
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dv=vector(1,nvar);
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for (i=1;i<=nvar;i++) {
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v[i]=vstart[i];
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y[i][1]=v[i];
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}
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xx[1]=x1;
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x=x1;
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h=(x2-x1)/nstep;
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for (k=1;k<=nstep;k++) {
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(*derivs)(x,v,dv);
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rk4(v,dv,nvar,x,h,vout,derivs);
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if ((float)(x+h) == x) nrerror("Step size too small in routine rkdumb");
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x += h;
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xx[k+1]=x;
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for (i=1;i<=nvar;i++) {
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v[i]=vout[i];
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y[i][k+1]=v[i];
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}
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}
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free_vector(dv,1,nvar);
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free_vector(vout,1,nvar);
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free_vector(v,1,nvar);
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}
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