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Re: Collect coefficients of array variables during calculation:

• To: mathgroup at smc.vnet.net
• Subject: [mg87035] Re: [mg86971] Collect coefficients of array variables during calculation:
• From: Sseziwa Mukasa <mukasa at jeol.com>
• Date: Sat, 29 Mar 2008 04:26:06 -0500 (EST)
• References: <200803280812.DAA04512@smc.vnet.net>

On Mar 28, 2008, at 4:12 AM, Gopinath Venkatesan 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.

Try this:

Simplify[10. A[[1, 1]] + b A[[1, 1]] + c A[[1, 2]] + 3. A[[1, 2]] /.
    A[[i__]] -> A[i]] /. A[i__] -> A[[i]]

Regards,

Sseziwa Mukasa

• References:
  • Collect coefficients of array variables during calculation:
    • From: Gopinath Venkatesan <gopinathv@ou.edu>