164 lines
5.3 KiB
C++

#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
#include <chrono>
#include <omp.h>
// =====================
// Matrizen erzeugen
// =====================
void generateRandomMatrices(int n,
std::vector<std::vector<double>>& A,
std::vector<std::vector<double>>& B,
double min_val = 0.0,
double max_val = 10.0)
{
std::srand(static_cast<unsigned int>(std::time(nullptr)));
A.resize(n, std::vector<double>(n));
B.resize(n, std::vector<double>(n));
for (int i = 0; i < n; ++i)
for (int j = 0; j < n; ++j)
{
double r1 = static_cast<double>(std::rand()) / RAND_MAX;
double r2 = static_cast<double>(std::rand()) / RAND_MAX;
A[i][j] = min_val + r1 * (max_val - min_val);
B[i][j] = min_val + r2 * (max_val - min_val);
}
}
// =====================
// Serielle Multiplikation
// =====================
std::vector<std::vector<double>> matmul_serial(const std::vector<std::vector<double>>& A,
const std::vector<std::vector<double>>& B)
{
int n = A.size();
int m = B[0].size();
int p = B.size();
std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
for (int i = 0; i < n; ++i)
for (int j = 0; j < m; ++j)
for (int k = 0; k < p; ++k)
C[i][j] += A[i][k] * B[k][j];
return C;
}
// =====================
// Parallele Zeilenzerlegung
// =====================
std::vector<std::vector<double>> matmul_row_parallel(const std::vector<std::vector<double>>& A,
const std::vector<std::vector<double>>& B,
int numThreads)
{
int n = A.size();
int m = B[0].size();
int p = B.size();
std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
omp_set_num_threads(numThreads);
#pragma omp parallel for
for (int i = 0; i < n; ++i)
for (int j = 0; j < m; ++j)
for (int k = 0; k < p; ++k)
C[i][j] += A[i][k] * B[k][j];
return C;
}
// =====================
// Parallele Spaltenzerlegung
// =====================
std::vector<std::vector<double>> matmul_col_parallel(const std::vector<std::vector<double>>& A,
const std::vector<std::vector<double>>& B,
int numThreads)
{
int n = A.size();
int m = B[0].size();
int p = B.size();
std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
omp_set_num_threads(numThreads);
#pragma omp parallel for
for (int j = 0; j < m; ++j)
for (int i = 0; i < n; ++i)
for (int k = 0; k < p; ++k)
C[i][j] += A[i][k] * B[k][j];
return C;
}
// =====================
// Parallele Blockzerlegung
// =====================
std::vector<std::vector<double>> matmul_block_parallel(const std::vector<std::vector<double>>& A,
const std::vector<std::vector<double>>& B,
int blockSize,
int numThreads)
{
int n = A.size();
int m = B[0].size();
int p = B.size();
std::vector<std::vector<double>> C(n, std::vector<double>(m, 0.0));
omp_set_num_threads(numThreads);
#pragma omp parallel for collapse(2)
for (int ii = 0; ii < n; ii += blockSize)
for (int jj = 0; jj < m; jj += blockSize)
for (int i = ii; i < std::min(ii + blockSize, n); ++i)
for (int j = jj; j < std::min(jj + blockSize, m); ++j)
for (int k = 0; k < p; ++k)
C[i][j] += A[i][k] * B[k][j];
return C;
}
// =====================
// Main
// =====================
int main()
{
int N = 500; // Matrixgröße anpassen
int numThreads = 4; // Threads für OpenMP
int blockSize = 64; // Blockgröße für Blockmultiplikation
std::vector<std::vector<double>> A, B;
generateRandomMatrices(N, A, B);
// ---------- Seriell ----------
auto start = std::chrono::steady_clock::now();
auto C_serial = matmul_serial(A, B);
auto end = std::chrono::steady_clock::now();
std::cout << "Seriell: " << std::chrono::duration<double>(end-start).count() << " s\n";
// ---------- Zeilenparallel ----------
start = std::chrono::steady_clock::now();
auto C_row = matmul_row_parallel(A, B, numThreads);
end = std::chrono::steady_clock::now();
std::cout << "Zeilenparallel: " << std::chrono::duration<double>(end-start).count() << " s\n";
// ---------- Spaltenparallel ----------
start = std::chrono::steady_clock::now();
auto C_col = matmul_col_parallel(A, B, numThreads);
end = std::chrono::steady_clock::now();
std::cout << "Spaltenparallel: " << std::chrono::duration<double>(end-start).count() << " s\n";
// ---------- Blockparallel ----------
start = std::chrono::steady_clock::now();
auto C_block = matmul_block_parallel(A, B, blockSize, numThreads);
end = std::chrono::steady_clock::now();
std::cout << "Blockparallel: " << std::chrono::duration<double>(end-start).count() << " s\n";
return 0;
}