Function: mathnfmod
Section: linear_algebra
C-Name: hnfmod
Prototype: GG
Help: mathnfmod(x,d): (upper triangular) Hermite normal form of x, basis for
 the lattice formed by the columns of x, where d is a multiple of the
 non-zero determinant of this lattice.
Doc: if $x$ is a (not necessarily square) matrix of
 maximal rank with integer entries, and $d$ is a multiple of the (non-zero)
 determinant of the lattice spanned by the columns of $x$, finds the
 \emph{upper triangular} \idx{Hermite normal form} of $x$.

 If the rank of $x$ is equal to its number of rows, the result is a square
 matrix. In general, the columns of the result form a basis of the lattice
 spanned by the columns of $x$. Even when $d$ is known, this is in general
 slower than \kbd{mathnf} but uses much less memory.
