#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_