82 lines
2.1 KiB
C++
82 lines
2.1 KiB
C++
#include "matrix.hpp"
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#include <omp.h>
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int **D {nullptr};
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// wavefront computation
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void wavefront_omp(unsigned num_threads) {
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// set up the dependency matrix
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D = new int *[MB];
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for(int i=0; i<MB; ++i) D[i] = new int [NB];
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for(int i=0; i<MB; ++i){
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for(int j=0; j<NB; ++j){
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D[i][j] = 0;
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}
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}
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omp_set_num_threads(num_threads);
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#pragma omp parallel
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{
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#pragma omp single
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{
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matrix[M-1][N-1] = 0;
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for( int k=1; k <= 2*MB-1; k++) {
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int i, j;
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if(k <= MB){
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i = k-1;
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j = 0;
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}
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else{
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//assume matrix is square
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i = MB-1;
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j = k-MB;
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}
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for(; (k <= MB && i>=0) || (k > MB && j <= NB-1) ; i--, j++){
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if(i > 0 && j > 0){
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#pragma omp task depend(in:D[i-1][j], D[i][j-1]) depend(out:D[i][j]) firstprivate(i, j)
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block_computation(i, j);
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}
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//top left corner
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else if(i == 0 && j == 0){
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#pragma omp task depend(out:D[i][j]) firstprivate(i, j)
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block_computation(i, j);
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}
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//top edge
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else if(j+1 <= NB && i == 0 && j > 0){
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#pragma omp task depend(in:D[i][j-1]) depend(out:D[i][j]) firstprivate(i, j)
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block_computation(i, j);
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}
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//left edge
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else if(i+1 <= MB && i > 0 && j == 0){
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#pragma omp task depend(in:D[i-1][j]) depend(out:D[i][j]) firstprivate(i, j)
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block_computation(i, j);
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}
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//bottom right corner
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else if(i == MB-1 && j == NB-1){
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#pragma omp task depend(in:D[i-1][j] ,D[i][j-1]) firstprivate(i, j)
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block_computation(i, j);
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}
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else{
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assert(false);
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}
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}
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}
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#pragma omp taskwait
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}
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}
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for ( int i = 0; i < MB; ++i ) delete [] D[i];
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delete [] D;
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}
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std::chrono::microseconds measure_time_omp(unsigned num_threads) {
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auto beg = std::chrono::high_resolution_clock::now();
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wavefront_omp(num_threads);
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auto end = std::chrono::high_resolution_clock::now();
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return std::chrono::duration_cast<std::chrono::microseconds>(end - beg);
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}
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