MathGroup Archive 2005

[Date Index] [Thread Index] [Author Index]

Search the Archive

Replacing an expression by an expression


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?


  • Prev by Date: Simplifying Jacobian elliptic functions
  • Next by Date: Re: exploded plots
  • Previous by thread: Simplifying Jacobian elliptic functions
  • Next by thread: Re: Mathematica hangs when solving sys. of equations w/certain parameters