From 53924dabb046e212f3aa27cb2a21dc7b0842308f Mon Sep 17 00:00:00 2001 From: Richard Kreckel Date: Tue, 25 Sep 2001 21:18:45 +0000 Subject: [PATCH] - clarify comment about counterintuitive sorting for Laplace. --- ginac/matrix.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) 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