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Re: Re: Linear Programming

  • To: mathgroup at smc.vnet.net
  • Subject: [mg51029] Re: [mg51011] Re: [mg50977] Linear Programming
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Sat, 2 Oct 2004 03:17:57 -0400 (EDT)
  • References: <200409300852.EAA26529@smc.vnet.net> <200410010849.EAA11582@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

It's a kind of disclaimer. If you do not know what they are good for 
ask a lawyer ;-)

You can avoid it by specifying some upper bounds for x and y, e.g.


NMinimize[{x + y, 100 >= x >= 5, 100 >= y >= 5,
    3*x >= 5*y, {x, y} $B":(B Integers}, {x, y}]


{14., {x -> 9, y -> 5}}



Andrzej Kozlowski

On 1 Oct 2004, at 17:49, DrBob wrote:

> *This message was transferred with a trial version of CommuniGate(tm) 
> Pro*
> This works, but it throws a meaningless error first:
>
> NMinimize[{x + y, x >= 5, y >= 5,
>     3*x >= 5*y, {x, y} \[Element] Integers},
>    {x, y}]
>
> \!\(\*
>    RowBox[{\(NMinimize::"incst"\), \(\(:\)\(\ \)\), 
> "\<\"\\!\\(NMinimize\\)
>      was unable to generate any
>        initial points satisfying the inequality constraints \
> \\!\\({\\(\\(\\(\\(\\(\\(-3\\)\\)\\\\ \\(\\(Round[x]\\)\\)\\)\\) + \
> \\(\\(5\\\\ \\(\\(Round[y]\\)\\)\\)\\)\\)\\) ? 0}\\). The initial 
> region \
> specified may not contain any feasible points. Changing the initial 
> region or \
> specifying explicit initial points may provide a better solution. \
> \\!\\(\\*ButtonBox[\\\"More?\\\", 
> ButtonStyle->\\\"RefGuideLinkText\\\", \
> ButtonFrame->None, ButtonData:>\\\"NMinimize::incst\\\"]\\)\"\>"}]\)
>
> {14., {x -> 9, y -> 5}}
>
> Perhaps somebody out there can explain why this error message is "a 
> good thing"?
>
> Bobby
>
> On Thu, 30 Sep 2004 04:52:32 -0400 (EDT), Rodrigo Malacarne 
> <malacarne at gmail.com> wrote:
>
>> Hi everybody,
>>
>> How can I insert a constraint in the following expression
>>
>> ConstrainedMin[x+y,{x>5,y>5,3x>5y},{x,y}]
>>
>> to find only integer results? Using the expression above I get
>>
>> {13.3333,{x->8.3333,y->5.}}
>>
>> but I want x to be an integer number.
>>
>> Cordially yours,
>> Rodrigo
>>
>>
>>
>>
>
>
>
> -- 
> DrBob at bigfoot.com
> www.eclecticdreams.net
>


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