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MathGroup Archive 2004

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Re: Defining a function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49847] Re: [mg49830] Defining a function
  • From: DrBob <drbob at bigfoot.com>
  • Date: Wed, 4 Aug 2004 10:46:24 -0400 (EDT)
  • References: <200408030511.BAA00173@smc.vnet.net>
  • Reply-to: drbob at bigfoot.com
  • Sender: owner-wri-mathgroup at wolfram.com

For instance:

<< Calculus`Integration`
f[k_] := Sum[a[i, k - i]Boole[1 â?¤ k - i â?¤ n], {i, 1, m}]

f /@ Range[13] /. {m -> 10, n -> 3} // ColumnForm

0
a[1, 1]
a[1, 2] + a[2, 1]
a[1, 3] + a[2, 2] + a[3, 1]
a[2, 3] + a[3, 2] + a[4, 1]
a[3, 3] + a[4, 2] + a[5, 1]
a[4, 3] + a[5, 2] + a[6, 1]
a[5, 3] + a[6, 2] + a[7, 1]
a[6, 3] + a[7, 2] + a[8, 1]
a[7, 3] + a[8, 2] + a[9, 1]
a[8, 3] + a[9, 2] + a[10, 1]
a[9, 3] + a[10, 2]
a[10, 3]

Bobby

On Tue, 3 Aug 2004 01:11:02 -0400 (EDT), PSi <psinome at tee.gr> wrote:

> I want to compute the Sum[a[i, j]] as a function of k when
> 1 <= i <= m,  1 <= j <= n and i+j=k. The numbers m, n and
> the function a[i, j] are given. Is it possible to define such a
> function with Mathematica 4.1?
> Thanks, PSi
>
>
>
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net


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