156 lines
4.0 KiB
C++
156 lines
4.0 KiB
C++
#ifndef _matvec_n_
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#define _matvec_n_
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#include "./utils/matrix.h"
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#include "./core/omp_config.h"
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namespace numerics{
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// =================================================
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// y = A * x (Matrix–Vector product)
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// =================================================
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template <typename T>
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utils::Vector<T> matvec(const utils::Matrix<T>& A, const utils::Vector<T>& x) {
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if (A.cols() != x.size()) {
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throw std::runtime_error("matvec: dimension mismatch");
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}
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const uint64_t m = A.rows();
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const uint64_t n = A.cols();
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utils::Vector<T> y(m, T{0});
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for (uint64_t i = 0; i < m; ++i) {
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for (uint64_t j = 0; j < n; ++j) {
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y[i] += A(i, j) * x[j];
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}
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}
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return y;
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}
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// -------------- Collapse(2) OpenMP ----------------
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template <typename T>
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utils::Vector<T> matvec_omp(const utils::Matrix<T>& A, const utils::Vector<T>& x) {
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if (A.cols() != x.size()) {
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throw std::runtime_error("matvec: dimension mismatch");
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}
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const uint64_t m = A.rows();
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const uint64_t n = A.cols();
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utils::Vector<T> y(m, T{0}); // <-- y has length m (rows)
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const T* xptr = x.data();
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const T* Aptr = A.data(); // row-major: A(i,j) == Aptr[i*n + j]
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// Each row i is an independent dot product: y[i] = dot(A[i,*], x)
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#pragma omp parallel for schedule(static)
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for (uint64_t i = 0; i < m; ++i) {
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const T* row = Aptr + i * n; // contiguous row i
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T acc = T{0};
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#pragma omp simd reduction(+:acc)
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for (uint64_t j = 0; j < n; ++j) {
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acc += row[j] * xptr[j];
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}
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y[i] = acc;
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}
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return y;
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}
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// -------------- Auto OpenMP ----------------
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template <typename T>
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utils::Vector<T> matvec_auto(const utils::Matrix<T>& A,
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const utils::Vector<T>& x) {
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uint64_t work = A.rows() * A.cols();
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bool can_parallel = omp_config::omp_parallel_allowed();
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#ifdef _OPENMP
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int threads = omp_get_max_threads();
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#else
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int threads = 1;
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#endif
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if (can_parallel || work > static_cast<uint64_t>(threads) * 4ull) {
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return matvec_omp(A,x);
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}
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else{
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// Safe fallback
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return matvec(A,x);
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}
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}
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// =================================================
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// y = x * A (Vector–Matrix product)
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// =================================================
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template <typename T>
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utils::Vector<T> vecmat(const utils::Vector<T>& x, const utils::Matrix<T>& A) {
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if (x.size() != A.rows()) {
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throw std::runtime_error("vecmat: dimension mismatch");
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}
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const uint64_t m = A.rows();
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const uint64_t n = A.cols();
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utils::Vector<T> y(n, T{0});
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for (uint64_t j = 0; j < n; ++j) {
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for (uint64_t i = 0; i < m; ++i) {
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y[j] += x[i] * A(i, j);
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}
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}
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return y;
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}
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// -------------- Collapse(2) OpenMP ----------------
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template <typename T>
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utils::Vector<T> vecmat_omp(const utils::Vector<T>& x, const utils::Matrix<T>& A) {
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if (x.size() != A.rows()) {
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throw std::runtime_error("vecmat: dimension mismatch");
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}
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const uint64_t m = A.rows();
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const uint64_t n = A.cols();
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utils::Vector<T> y(n, T{0});
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#pragma omp parallel for schedule(static)
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for (uint64_t j = 0; j < n; ++j) {
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T acc = T{0};
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for (uint64_t i = 0; i < m; ++i) {
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acc += x[i] * A(i, j);
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}
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y[j] = acc;
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}
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return y;
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}
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// -------------- Auto OpenMP ----------------
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template <typename T>
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utils::Vector<T> vecmat_auto(const utils::Vector<T>& x,
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const utils::Matrix<T>& A) {
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uint64_t work = A.rows() * A.cols();
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bool can_parallel = omp_config::omp_parallel_allowed();
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#ifdef _OPENMP
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int threads = omp_get_max_threads();
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#else
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int threads = 1;
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#endif
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if (can_parallel || work > static_cast<uint64_t>(threads) * 4ull) {
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return vecmat_omp(x,A);
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}
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else{
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// Safe fallback
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return vecmat(x,A);
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}
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}
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} // namespace numerics
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#endif // _matvec_n_
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