In a recent post in this thread, Savdeep Sethi pointed out that at least for certain computations LiE is much faster than Sage for decomposing tensor powers of representations. In analyzing why this is true, I tried replacing the current algorithm, which is the product_on_basis method of WeylCharacterRings, by the Brauer-Klimyk algorithm. This turned out to be remarkably effective. I made a trac ticket here:
http://trac.sagemath.org/sage_trac/ticket/13391 After the patch, taking the tensor powers of the spin representation of B4 (which was the example Savdeep gave) I can get up to the 12 or 13th power. Before the patch, even the 6th tensor power is slow. With LiE, Savdeep got up to the 16th power, so there is still room for improvement. The Brauer-Klimyk algorithm is the algorithm used by LiE. Dan -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To view this discussion on the web visit https://groups.google.com/d/msg/sage-combinat-devel/-/0mKYDdn5FH4J. To post to this group, send email to sage-combinat-devel@googlegroups.com. To unsubscribe from this group, send email to sage-combinat-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.
