1Function: matindexrank 2Section: linear_algebra 3C-Name: indexrank 4Prototype: G 5Description: 6 (gen):vecvecsmall indexrank($1) 7Help: matindexrank(M): gives two extraction vectors (rows and columns) for 8 the matrix M such that the extracted matrix is square of maximal rank. 9Doc: $M$ being a matrix of rank $r$, returns a vector with two 10 \typ{VECSMALL} components $y$ and $z$ of length $r$ giving a list of rows 11 and columns respectively (starting from 1) such that the extracted matrix 12 obtained from these two vectors using $\tet{vecextract}(M,y,z)$ is 13 invertible. The vectors $y$ and $z$ are sorted in increasing order. 14