Re: Applying transformation rule to matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg9822] Re: [mg9720] Applying transformation rule to matrix
- From: Wouter Meeussen <vdmcc at vandemoortele.be>
- Date: Fri, 28 Nov 1997 05:35:36 -0500
- Sender: owner-wri-mathgroup at wolfram.com
hi Gary,
try
bigrule = Thread[Rule[Flatten at pos,Flatten at posval]]
also look at the Book under "Dispach tables" if speed counts.
wouter.
At 12:06 25.11.97 -0500, you wrote:
>I have a symbolic matrix created as
>
> pos=Array[p,{4,3}]
>
>and a corresponding matrix that stores actual values, e.g.,
>
> posval={{1,2,3},{4,5,6},{7,8,9},{1,2,3}}
>
>I perform some operations on "pos" to get several other variables and
>now I'd like to apply a transformation rule to see what the numerical
>value of those resulting variables is with the values in "posval".
>Assuming "var1" is some function of the elements in the matrix "pos",
>is there an easier way to do this than:
>
> var1 /. {pos[[1,1]]->posval[[1,1]],...,pos[[4,3]]->posval[[4,3]]}
>
>The string of transformation rules in {}'s gets quite long for a 4x3
>matrix and it's a bit annoying having to cut and paste the thing
>around. I don't want to assign pos=posval because I may define other
>symbolic variables that are functions of "pos" later.
>
>Of importance may be that I'm using v2.2 on a Sparc under Solaris.
>
>I'm still learning Mathematica so be gentle if this is a dumb question!
>
>Thanks,
>Gary
>
>
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