68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
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#include <math.h>
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#include <string.h>
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#include "timer.h"
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#include <stdio.h>
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#define NN 1024
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#define NM 1024
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float A[NN][NM];
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float Anew[NN][NM];
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int main(int argc, char** argv)
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{
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int i,j;
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const int n = NN;
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const int m = NM;
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const int iter_max = 1000;
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const double tol = 1.0e-6;
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double error = 1.0;
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memset(A, 0, n * m * sizeof(float));
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memset(Anew, 0, n * m * sizeof(float));
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for (j = 0; j < n; j++)
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{
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A[j][0] = 1.0;
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Anew[j][0] = 1.0;
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}
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printf("Jacobi relaxation Calculation: %d x %d mesh\n", n, m);
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StartTimer();
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int iter = 0;
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while ( error > tol && iter < iter_max )
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{
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error = 0.0;
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for( j = 1; j < n-1; j++)
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{
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for( i = 1; i < m-1; i++ )
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{
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Anew[j][i] = 0.25 * ( A[j][i+1] + A[j][i-1]
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+ A[j-1][i] + A[j+1][i]);
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error = fmax( error, fabs(Anew[j][i] - A[j][i]));
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}
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}
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for( j = 1; j < n-1; j++)
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{
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for( i = 1; i < m-1; i++ )
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{
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A[j][i] = Anew[j][i];
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}
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}
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if(iter % 100 == 0) printf("%5d, %0.6f\n", iter, error);
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iter++;
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}
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double runtime = GetTimer();
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printf(" total: %f s\n", runtime / 1000);
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return 0;
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}
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