ready for parralization

include/numerics/matvec.h

@@ -0,0 +1,54 @@
+#ifndef _matvec_n_
+#define _matvec_n_
+
+
+#include "./utils/matrix.h"
+
+
+namespace numerics{
+	
+	// y = A * x, where A is (m×n) and x is length n and y is length m
+	template <typename T>
+	utils::Vector<T> matvec(const utils::Matrix<T>& A, const utils::Vector<T>& x) {
+	    if (A.cols() != x.size()) {
+	        throw std::runtime_error("matvec: dimension mismatch");
+	    }
+
+	    const uint64_t m = A.rows();
+	    const uint64_t n = A.cols();
+
+	    utils::Vector<T> y(m, T{0});
+	    for (uint64_t i = 0; i < m; ++i) {
+	        T acc = T{0};
+	        for (uint64_t j = 0; j < n; ++j) {
+	            acc += A(i, j) * x[j];
+	        }
+	        y[i] = acc;
+	    }
+	    return y;
+	}
+
+	// y = x * A, where x is length m and A is (m×n) -> y is length n
+	template <typename T>
+	utils::Vector<T> vecmat(const utils::Vector<T>& x, const utils::Matrix<T>& A) {
+	    if (x.size() != A.rows()) {
+	        throw std::runtime_error("vecmat: dimension mismatch");
+	    }
+	    const uint64_t m = A.rows();
+	    const uint64_t n = A.cols();
+
+	    utils::Vector<T> y(n, T{0});
+	    for (uint64_t j = 0; j < n; ++j) {
+	        T acc = T{0};
+	        for (uint64_t i = 0; i < m; ++i) {
+	            acc += x[i] * A(i, j);
+	        }
+	        y[j] = acc;
+	    }
+	    return y;
+	}
+
+
+} // namespace numerics
+
+#endif // _matvec_n_