generated from freudenreichan/Programmieren_3b
95 lines
2.7 KiB
C++
95 lines
2.7 KiB
C++
#include <vector>
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#include <chrono>
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#include <iostream>
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#include <omp.h>
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#include <cstdlib>
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#include <ctime>
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// Zufallsmatrizen erzeugen
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void generateRandomMatrices(int n,
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std::vector<std::vector<double>>& A,
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std::vector<std::vector<double>>& B)
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{
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std::srand(static_cast<unsigned int>(std::time(nullptr)));
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A.resize(n, std::vector<double>(n));
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B.resize(n, std::vector<double>(n));
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for (int i = 0; i < n; ++i)
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for (int j = 0; j < n; ++j)
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{
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A[i][j] = static_cast<double>(rand()) / RAND_MAX * 10.0;
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B[i][j] = static_cast<double>(rand()) / RAND_MAX * 10.0;
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}
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}
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// Serielle Matrizenmultiplikation
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std::vector<std::vector<double>> matmul_serial(
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const std::vector<std::vector<double>>& A,
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const std::vector<std::vector<double>>& B)
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{
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int n = A.size();
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int m = B[0].size();
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int p = B.size();
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std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
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for (int i = 0; i < n; ++i)
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for (int j = 0; j < m; ++j)
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for (int k = 0; k < p; ++k)
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C[i][j] += A[i][k] * B[k][j];
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return C;
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}
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// Spaltenparallel (Column-parallel)
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std::vector<std::vector<double>> matmul_column_parallel(
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const std::vector<std::vector<double>>& A,
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const std::vector<std::vector<double>>& B)
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{
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int n = A.size();
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int m = B[0].size();
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int p = B.size();
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std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
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#pragma omp parallel for
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for (int j = 0; j < m; ++j) // Spalten parallel
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for (int i = 0; i < n; ++i)
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for (int k = 0; k < p; ++k)
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C[i][j] += A[i][k] * B[k][j];
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return C;
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}
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// -----------------------------
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int main()
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{
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int N = 500;
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std::vector<std::vector<double>> A, B;
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generateRandomMatrices(N, A, B);
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// Serielle Version
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auto start = std::chrono::steady_clock::now();
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auto C_serial = matmul_serial(A, B);
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auto end = std::chrono::steady_clock::now();
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std::cout << "Serial multiplication took: "
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<< std::chrono::duration<double>(end - start).count() << "s\n";
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// Spaltenparallel
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start = std::chrono::steady_clock::now();
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auto C_col = matmul_column_parallel(A, B);
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end = std::chrono::steady_clock::now();
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std::cout << "Column-parallel multiplication took: "
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<< std::chrono::duration<double>(end - start).count() << "s\n";
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// Vergleich
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for (int i = 0; i < N; ++i)
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for (int j = 0; j < N; ++j)
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if (C_serial[i][j] != C_col[i][j])
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{
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std::cout << "Mismatch at " << i << "," << j << "\n";
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return 1;
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}
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std::cout << "All results match!\n";
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return 0;
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}
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