\\% Permanent of a matrix.
\\ Author: Joerg Arndt
\\ License: GPL version 3 or later
\\ online at http://www.jjj.de/pari/
\\ version: 2011-January-19 (12:49)

matperm(M)=
{
    local(n, ret, pm);
    n = matsize(M)[1];
    if ( n!=matsize(M)[2], error("matperm: M must be square matrix.") );
    ret = 0;
    for (k=0, n!-1,
        pm = numtoperm(n, k);
        ret += prod(j=1,n, M[j, pm[j] ])
    );
    return(ret);
} /* ----- */


\\ ==== end of file ====