Replacing an expression by an expression
- To: mathgroup at smc.vnet.net
- Subject: [mg55625] Replacing an expression by an expression
- From: carlos at colorado.edu
- Date: Thu, 31 Mar 2005 01:24:56 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
I have a 8 x 8 symbolic matrix B of complicated entries.
Several partial expressions, however, can be simplified. Sample:
rep= {(J12*x14-J11*y14)*(J12*(x32+x43)-J11*(y32+y43)) -> A0*(A1-A0)};
The left expression appears verbatim in entry B[[1,1]], which is
-(L21*(J12*x14-J11*y14)*(J12*(-x32-x43)+J11*(y32+y43)))/
(16*A412*J*(J11^2+J12^2))
But when I say B=B/.rep, nothing happens. For a few entries I could do
cut and paste by hand:
-(L21* A0*(A1-A0) )/
(16*A412*J*(J11^2+J12^2))
But it get tedious and error prone for 64. Any suggestions on how to
get Mathematica to do the replacement?