Re: Non trivial substitution in a very long output
- To: mathgroup at smc.vnet.net
- Subject: [mg123164] Re: Non trivial substitution in a very long output
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Fri, 25 Nov 2011 04:54:52 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201111241156.GAA28999@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
It seems to work fine in this example: piece = Abs[b41]^2 + Abs[b51]^2 + Abs[b61]^2 + Abs[(b61 x1 + b51 x2 + b41 x3)/x4]^2 + Abs[(b61 x2 + b51 x3 + b41 x4)/x1]^2 + Abs[(b61 x1 x3 + b51 (x2 x3 - x1 x4) + b41 (x3^2 - x2 x4))/ x4^2]^2 + Abs[(b61 (x1 x3^2 - x1 x2 x4) + b51 (x2 x3^2 - x2^2 x4 - x1 x3 x4) + b41 (x3^3 - 2 x2 x3 x4 + x1 x4^2))/x4^3]^2; expr = piece + piece^2 - Sin@piece; expr //. piece -> p p + p^2 - Sin[p] Bobby On Thu, 24 Nov 2011 05:56:33 -0600, Demind <demind at gmail.com> wrote: > Hello, my name is Marco. I am experiencing an annoying problem using > Mathematica. I am dealing with a huge expression, some hundreds of > lines. I can find 3/4 patterns repeating inside it, and I would really > like to substitute thme with dummy variables, namely D1, D2, D3, D4. I'm > expecting the readibility of the equation to be improved after this > process. As it is right now, it's totally unreadable. I went through > past topics to find solutions to my problem, but unfortunately none of > the tricks I tried worked (mainly /. and //.). > > I give you a sample of what I would like to do, hoping that someone will > give me some help: > > In my equation, Out[1] = ... > the following pattern is repeated: > > Abs[b41]^2 + Abs[b51]^2 + Abs[b61]^2 + Abs[(b61 x1 + b51 x2 + b41 > x3)/x4]^2 + Abs[(b61 x2 + b51 x3 + b41 x4)/x1]^2 + Abs[(b61 x1 x3 + b51 > (x2 x3 - x1 x4) + b41 (x3^2 - x2 x4))/x4^2]^2 + Abs[(b61 (x1 x3^2 - x1 > x2 x4) + b51 (x2 x3^2 - x2^2 x4 - x1 x3 x4) + b41 (x3^3 - 2 x2 x3 x4 + > x1 x4^2))/x4^3]^2 > > I'm doing: > > Out[1] //. Abs[b41]^2 + Abs[b51]^2 + Abs[b61]^2 + Abs[(b61 x1 + b51 x2 + > b41 x3)/x4]^2 + Abs[(b61 x2 + b51 x3 + b41 x4)/x1]^2 + Abs[(b61 x1 x3 + > b51 (x2 x3 - x1 x4) + b41 (x3^2 - x2 x4))/x4^2]^2 + Abs[(b61 (x1 x3^2 - > x1 x2 x4) + b51 (x2 x3^2 - x2^2 x4 - x1 x3 x4) + b41 (x3^3 - 2 x2 x3 x4 > + x1 x4^2))/x4^3]^2 -> D1 > > Here the text is attached in "InputForm", where in my notebook I have it > in "StandardForm" (I use the latter in my notebook, but here I can't > reproduce it for obvious reasons). I tried to use the command above both > in StandardForm and in InputForm with no result. > > Thank you very much > > Marco > -- DrMajorBob at yahoo.com
- References:
- Non trivial substitution in a very long output
- From: Demind <demind@gmail.com>
- Non trivial substitution in a very long output