Re: Maximize with Integer constraints
- To: mathgroup at smc.vnet.net
- Subject: [mg78270] Re: Maximize with Integer constraints
- From: dh <dh at metrohm.ch>
- Date: Wed, 27 Jun 2007 05:29:12 -0400 (EDT)
- References: <f5qjmd$669$1@smc.vnet.net>
Hi,
that's a BUG! Wolfram should take note.
Mathematica screws up if you give real constrains for integers. Consider:
Maximize[{x,0<=x<=2},{x},Integers] gives {2,{x->2}}
Maximize[{x,0<=x<=2.},{x},Integers]gives {0.,{x->0}}
hope this helps, Daniel
sdw wrote:
> given entry #1:
>
>
> Maximize[
> {x1 + x2 + x3 + x4,
> Element[x1 | x2 | x3 | x4 , Integers] &&
> 0 <= x1 <= 5.6 &&
> 0 <= x2 <= 8.6 &&
> 0 <= x3 <= 9.7 &&
> 4.0 <= x4 <= 22.4 }, {x1, x2, x3, x4}]
>
> {4., {x1 -> 0, x2 -> 0, x3 -> 0, x4 -> 4}}
>
> note - zeros for answers
> entry #2:
> Maximize[
> {x1 + x2 + x3 + x4,
> Element[x1 | x2 | x3 | x4 , Integers] &&
> 0 <= x1 <= 5.6 &&
> 0 <= x2 <= 8.6 &&
> 0 <= x3 <= 9.7 &&
> 4.1 <= x4 <= 22.4 }, {x1, x2, x3, x4}]
>
> {44., {x1 -> 5, x2 -> 8, x3 -> 9, x4 -> 22}}
>
> note good answers...
> only difference is 4.1 vs. 4 in constraints
> any ideas what is going on?
>
> thanks,
>
> sdw
>
>