       Re: Constructing Expressions from List Elements

• To: mathgroup at smc.vnet.net
• Subject: [mg2207] Re: Constructing Expressions from List Elements
• From: ianc (Ian Collier)
• Date: Mon, 16 Oct 1995 11:53:15 -0400
• Organization: Wolfram Research, Inc.

```In article <44t3p9\$6t5 at ralph.vnet.net>, brianb at dendrite.cs.colorado.edu
(Brian Bonnlander) wrote:

> I have a list of integration limits that I would like to incorporate into
> an NIntegrate[] expression.  I don't know the proper syntax for accomplishing
> this.
>
> For example, I would like to integrate f[x,y,z] where the integration limits
> are contained in a list *limits*, expressed perhaps as
> limits = {{x, 0, 1}, {y, -Infinity, Infinity}, {z, 0, 1}}.
>
> The statement I would like to construct is
>
> NIntegrate[f[x,y,z], {x, 0, 1}, {y, -Infinity, Infinity}, {z, 0, 1}] .
>
>
> How do I remove the outer list braces for *limits* so that I can construct
> this statement?
>
>
> Thanks in advance,
>
> --Brian

You can substitute your own function for Sin[ x y z] in the following:

In:=
limits = {{x, 0, 1}, {y, -Infinity, Infinity}, {z, 0, 1}}
Out=
{{x, 0, 1}, {y, -Infinity, Infinity}, {z, 0, 1}}

In:=
Prepend[ limits, Sin[x y z] ]
Out=
{Sin[x y z], {x, 0, 1}, {y, -Infinity, Infinity}, {z, 0, 1}}

In:=
Apply[ NIntegrate, %]

Out=
1429
-4.89109 10

Alternativesare :

NIntegrate[Sin[x y z], ##]& @@ limits

NIntegrate[Sin[x y z], Sequence @@ limits]

I hope this helps.

--Ian

-----------------------------------------------------------
Ian Collier
Technical Sales Support
Wolfram Research, Inc.
-----------------------------------------------------------
tel:(217)-398-0700     fax:(217)-398-0747      ianc at wri.com