From eb48c4d6ce3591d116c85b3f4ab9d1ebb1095367 Mon Sep 17 00:00:00 2001 From: Michael Orlitzky Date: Wed, 3 Jul 2019 19:47:23 -0400 Subject: [PATCH] eja: add a comment about row/column vectors to eja_sn(). --- mjo/eja/euclidean_jordan_algebra.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mjo/eja/euclidean_jordan_algebra.py b/mjo/eja/euclidean_jordan_algebra.py index f71f75d..c47f400 100644 --- a/mjo/eja/euclidean_jordan_algebra.py +++ b/mjo/eja/euclidean_jordan_algebra.py @@ -643,9 +643,13 @@ def eja_sn(dimension, field=QQ): W = V.span( mat2vec(s) for s in S ) for s in S: - # Brute force the right-multiplication-by-s matrix by looping + # Brute force the multiplication-by-s matrix by looping # through all elements of the basis and doing the computation - # to find out what the corresponding row should be. + # to find out what the corresponding row should be. BEWARE: + # these multiplication tables won't be symmetric! It therefore + # becomes REALLY IMPORTANT that the underlying algebra + # constructor uses ROW vectors and not COLUMN vectors. That's + # why we're computing rows here and not columns. Q_rows = [] for t in S: this_row = mat2vec((s*t + t*s)/2) -- 2.44.2