From: Richard Kreckel Date: Tue, 25 Sep 2001 21:18:45 +0000 (+0000) Subject: - clarify comment about counterintuitive sorting for Laplace. X-Git-Tag: release_1-0-0~28 X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=commitdiff_plain;h=53924dabb046e212f3aa27cb2a21dc7b0842308f - clarify comment about counterintuitive sorting for Laplace. --- diff --git a/ginac/matrix.cpp b/ginac/matrix.cpp index c48fb6b1..e544210f 100644 --- a/ginac/matrix.cpp +++ b/ginac/matrix.cpp @@ -772,10 +772,13 @@ ex matrix::determinant(unsigned algo) const default: { // This is the minor expansion scheme. We always develop such // that the smallest minors (i.e, the trivial 1x1 ones) are on the - // rightmost column. For this to be efficient it turns out that - // the emptiest columns (i.e. the ones with most zeros) should be - // the ones on the right hand side. Therefore we presort the - // columns of the matrix: + // rightmost column. For this to be efficient, empirical tests + // have shown that the emptiest columns (i.e. the ones with most + // zeros) should be the ones on the right hand side -- although + // this might seem counter-intuitive (and in contradiction to some + // literature like the FORM manual). Please go ahead and test it + // if you don't believe me! Therefore we presort the columns of + // the matrix: typedef std::pair uintpair; std::vector c_zeros; // number of zeros in column for (unsigned c=0; c