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MathGroup Archive 1998

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Re: simplifying complex polynomials

  • To: mathgroup at smc.vnet.net
  • Subject: [mg13722] Re: [mg13699] simplifying complex polynomials
  • From: Wouter Meeussen <eu000949 at pophost.eunet.be>
  • Date: Wed, 19 Aug 1998 01:38:15 -0400
  • Sender: owner-wri-mathgroup at wolfram.com

Daniel,

lets create a sum of terms:

fa:=Apply[Plus,Table[(-1)^Random[Integer,{0,1}]
y@@Table[Random[Integer,{-1, 1}],{3}] ,{36},{4}],1]

ad let's make a rule:
ruletwo=(  a_Plus /;!MatchQ[(Plus@@(a/. -q->q/.Plus->List/.
y->List)),{2,_,_}]
  ->{})
let's create a sample:

fa
(#/.ruletwo&)/@%
%~DeleteCases~{}

this gives the list fa cleaned up.

wouter



At 04:39 15-08-98 -0400, Daniel H. Steinberg wrote:
>A friend of mine is trying to simplify polynomials which are sums of
>monomials each of which is the product of terms which are y_[] and z_[]
>where the [] is a vector like [1,1,2,1,5].
>
>Her simplification rules are fairly straightforward -- but how do you
>get Mathematica to do it.
>
>Rule 1: Each monomial must be quadratic in z (i.e. if it's not, replace
>it by 0)
>
>Rule 2: Each monomial's vector subscripts must sum (over all z's and
>y's) to the vector [1,2,2,2,1]  (for example). If it doesn't the term
>can be eliminated.
>
>Any thoughts? She's trying to process it as a list but this seems to be
>further complicated by multiplicities.
>
>Thanks, Daniel
>
>
Dr. Wouter L. J. MEEUSSEN
w.meeussen.vdmcc at vandemoortele.be
eu000949 at pophost.eunet.be



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