compute determinant from LU decomposition in lapack
问题 Lapack, most probably, doesn't have any routine for computing determinant. However we can compute it using either LU, QR or SVD decomposition. I prefer to use LU decomposition. Now lapack uses some dgetrf subroutine to factorize a matrix A into PLU format with some IPIV array. I don't have much idea how to deal with this information. To compute the determinant, I just multiply diagonal elements of U matrix. But what is L and U in PLU format and how to extract them. I am programming in C. 回答1: