On 04/04/2013 07:36 PM, Aaron Meurer wrote:
There's no easy way yet to define custom automatic multiplication (see
https://code.google.com/p/sympy/issues/detail?id=1941 and the pages
linked to there). It is possible to write a little helper function
that goes through an expression and rewrites products of Adds using
this algorithm.
Aaron Meurer
On Thu, Apr 4, 2013 at 5:12 PM, Alan Bromborsky <[email protected]> wrote:
let e_1,...,e_n bet a set of noncommutative symbols. Consider the sympy
expressions -
a = a_0+a_1*e_1+...+a_n*e_n
b = b_0+b_1*e_1+...+b_n*e_n
and you are given a multiplication table for the e_i's in the form of a
dictionary mul_table[(e_i,e_j)].
Each entry in the table is a linear combination of a scalar and the e_i's.
What is the most efficient way of performing the operation a*b where the
table results for e_i*e_j are
substituted (a*b is again a linear combination of a scalar and the e_i's).
For example is there a way of overloading the __mul__ operation for
expressions to test and substitute
for products of the form e_i*e_j?
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If the dictionary keys are e_i*e_j, that is multable[e_i*e_j] then would
(a*b).subs(multable) work?
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