Hi, I am trying to do a simple matrix inversion operation using boost. But I am getting an error. Basically what I am trying to find is inversted_matrix = inverse(trans(matrix) * matrix) But I am getting an error Check failed in file boost_1_53_0/boost/numeric/ublas/lu.hpp at line 299: detail::expression_type_check (prod (triangular_adaptor<const_matrix_type, upper> (m), e), cm2) terminate called after throwing an instance of 'boost::numeric::ublas::internal_logic' what(): internal logic Aborted (core dumped) My attempt: #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/vector.hpp> #include <boost/numeric/ublas/io.hpp> #include <boost/numeric/ublas/vector_proxy.hpp> #include <boost/numeric/ublas/matrix.hpp> #include <boost/numeric/ublas/triangular.hpp> #include <boost/numeric/ublas/lu.hpp> namespace ublas = boost::numeric::ublas; template<class T> bool InvertMatrix (const ublas::matrix<T>& input, ublas::matrix<T>& inverse) { using namespace boost::numeric::ublas; typedef permutation_matrix<std::size_t> pmatrix; // create a working copy of the input matrix<T> A(input); // create a permutation matrix for the LU-factorization pmatrix pm(A.size1()); // perform LU-factorization int res = lu_factorize(A,pm); if( res != 0 ) return false; // create identity matrix of "inverse" inverse.assign(ublas::identity_matrix<T>(A.size1())); // backsubstitute to get the inverse lu_substitute(A, pm, inverse); return true; } int main(){ using namespace boost::numeric::ublas; matrix<double> m(4,5); vector<double> v(4); vector<double> thetas; m(0,0) = 1; m(0,1) = 2104; m(0,2) = 5; m(0,3) = 1;m(0,4) = 45; m(1,0) = 1; m(1,1) = 1416; m(1,2) = 3; m(1,3) = 2;m(1,4) = 40; m(2,0) = 1; m(2,1) = 1534; m(2,2) = 3; m(2,3) = 2;m(2,4) = 30; m(3,0) = 1; m(3,1) = 852; m(3,2) = 2; m(3,3) = 1;m(3,4) = 36; std::cout<<m<<std::endl; matrix<double> product = prod(trans(m), m); std::cout<<product<<std::endl; matrix<double> inversion(5,5); bool inverted; inverted = InvertMatrix(product, inversion); std::cout<<inversion<<std::endl; } -- Mohit "When you want success as badly as you want the air, then you will get it. There is no other secret of success." -Socrates