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MathGroup Archive 2000

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Re: A Functional Programming Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg24708] Re: [mg24705] A Functional Programming Question
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Wed, 9 Aug 2000 02:31:08 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

The simplest "functional" soution that comes to my mind is:

In[15]:=
List @@ Last[Reduce[eqns, {x, y, z}]]
Out[15]=
{x == 0, y == 0, z == 0}

However, it is not quite claer if using a "mathematical" function like
Reduce should be considered an example of "functional programming". So here
is a more "conventional" solution:

In[19]:=
Inner[MapAt[Function[y, y/#1], #2, {1, 1}] &, {a, b, c}, {a x == 0, b y ==
0, c z == 0}, List]
Out[19]=
{x == 0, y == 0, z == 0}


e
Andrzej Kozlowski
Toyama International University, JAPAN

For Mathematica related links and resources try:
<http://www.sstreams.com/Mathematica/>



on 8/4/00 7:19 AM, David Park at djmp at earthlink.net wrote:

> Dear MathGroup,
> 
> Suppose I have three equations.
> 
> eqns = {a x == 0, b y == 0, c z == 0};
> 
> I want to divide out the constants a, b, and c. I can do it this way:
> 
> eqns[[1]] = (#1/a & ) /@ eqns[[1]];
> eqns[[2]] = (#1/b & ) /@ eqns[[2]];
> eqns[[3]] = (#1/c & ) /@ eqns[[3]];
> eqns
> 
> {x == 0, y == 0, z == 0}
> 
> Is there a simpler method for doing the calculation in one statement with
> functional programming, say using MapThread over eqns and {a,b,c}? Is there
> any other simple approach?
> 
> David Park
> djmp at earthlink.net
> http://home.earthlink.net/~djmp/
> 
> 
> 



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