21 lines
414 B
C
21 lines
414 B
C
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void relax2(double **u, double **rhs, int n)
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{
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int i,ipass,isw,j,jsw=1;
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double foh2,h,h2i,res;
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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=1;ipass<=2;ipass++,jsw=3-jsw) {
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isw=jsw;
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for (j=2;j<n;j++,isw=3-isw) {
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for (i=isw+1;i<n;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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