23 lines
445 B
C++
23 lines
445 B
C++
#include "nr.h"
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void NR::relax2(Mat_IO_DP &u, Mat_I_DP &rhs)
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{
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int i,ipass,isw,j,jsw=1;
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DP foh2,h,h2i,res;
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int n=u.nrows();
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h=1.0/(n-1);
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h2i=1.0/(h*h);
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foh2 = -4.0*h2i;
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for (ipass=0;ipass<2;ipass++,jsw=3-jsw) {
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isw=jsw;
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for (j=1;j<n-1;j++,isw=3-isw) {
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for (i=isw;i<n-1;i+=2) {
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res=h2i*(u[i+1][j]+u[i-1][j]+u[i][j+1]+u[i][j-1]-
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4.0*u[i][j])+u[i][j]*u[i][j]-rhs[i][j];
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u[i][j] -= res/(foh2+2.0*u[i][j]);
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}
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}
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}
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}
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