README.Eigen.md

Eigen Matrix Market

fast_matrix_market provides read/write methods for Eigen sparse matrices, dense matrices, and dense vectors.

Usage

#include <fast_matrix_market/app/Eigen.hpp>

Reading

Sparse:

std::ifstream f("input.mtx");

Eigen::SparseMatrix<double> mat;
fast_matrix_market::read_matrix_market_eigen(f, mat);

Dense Matrix/Vector is the same, using read_matrix_market_eigen_dense:

std::ifstream f("input.mtx", std::ios_base::binary);

Eigen::VectorXd vec;
fast_matrix_market::read_matrix_market_eigen_dense(f, vec);

Writing

std::ofstream f("output.mtx", std::ios_base::binary);

Eigen::SparseMatrix<double> mat;
fast_matrix_market::write_matrix_market_eigen(f, mat);

Again, for dense matrices/vectors use write_matrix_market_eigen_dense.

Not restricted to double matrices. Any type supported by Eigen that makes sense in Matrix Market is also supported, such as int64_t, float, std::complex<double>, etc.

Note that Vectors are written with object type = matrix for compatibility reasons. Eigen's saveMarketVector() does the same. As of writing Eigen's loader crashes on vector files.