Re: Collect coefficients of array variables during

• To: mathgroup at smc.vnet.net
• Subject: [mg87013] Re: [mg86971] Collect coefficients of array variables during
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sat, 29 Mar 2008 04:21:56 -0500 (EST)

```Off[Part::partd, Part::pspec];

eqn1 = 10. A[[1, 1]] + b A[[1, 1]] + c A[[1, 2]] + 3. A[[1, 2]];

eqn1 // Simplify

(b+10.) A[[1,1]]+(c+3.) A[[1,2]]

If Simplify doesn't work try FullSimplify or hit it with a hammer:

Collect[eqn1, Union[Cases[eqn1, A[[__]], Infinity]]]

(b+10.) A[[1,1]]+(c+3.) A[[1,2]]

Bob Hanlon

---- Gopinath Venkatesan <gopinathv at ou.edu> wrote:
> Hello Mathematica Friends
>
> If we have an array variable, and assuming after intermediate calculations, some equations are found to be below.
>
> eqn1=10. A[[1,1]]+b A[[1,1]]+c A[[1,2]]+3. A[[1,2]] (only for illustration)
>
> Simplify[] does not combine the coefficients under same array member, i.e. instead of (10.+b)A[[1,1]]+(c+3.)A[[1,2]], it is showing the earlier mentioned form.
>
> Is there a way to collect them and simplify them. But when I checked for simple cases, Simplify[] seems to work.
>
> Thanks for the suggestions.
>
> Regards,
> Gopinath
> University of Oklahoma
>

```

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