efficient term collection algorithm

*To*: mathgroup at smc.vnet.net*Subject*: [mg69155] efficient term collection algorithm*From*: Blake Laing <laing at nhn.ou.edu>*Date*: Thu, 31 Aug 2006 04:39:14 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Dear Math Group I wish to combine terms in a expression which share a denominator, such as in the following simple case: In[1]:= a/i+b/j+c/i//.Plus[Times[A_.,Power[denom_,-1]],Times[B_.,Power[denom_,-1]]]:> Factor[Plus[A,B]Power[denom,-1]]//InputForm Out[1]//InputForm= (a + c)/i + b/j The actual expression I am working with contains thousands of terms, and a pairwise algorithm such as this is wholly inadequate. Will one of you please suggest a more efficient way to combine each additive term in a large expression with a shared denominator? Thanks, Blake Laing physics grad student University of Oklahoma