need HELP for define Variable boundary

GAMS
1

Hi

I have serious problem with defining a variable NOT to be between two number

for example X>2 and X<0.1

How should i write this boundary in GAMS equations?

Thanks for your help in advance!

Azad

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2

So you mean that X can be either in (-inf, 0.1) or (2, inf)?

For starters, the strict inequalities are a problem. See Arne’s response from this post from a few months ago: https://groups.google.com/d/msg/gamsworld/l3Vkkss6cQQ/ofAZR-vMSQMJ

If you can settle for non-strict inequality, like X >= a and X = 0) and when x >= b (because x-a >= 0 and b-x 2 and X<0.1

How should i write this boundary in GAMS equations?

Thanks for your help in advance!

Azad

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3

Thanks for the help dear Trish

I use the advice and define my variable as :

positive variables
usage(n,a,h)

usage.up(n,a,h) = ((E(a)/time(a))+0.2);

loadieq(n,a,h) … (usage(n,a,h)-0.01 )* ((E(a)/time(a))- usage(n,a,h) ) =l= 0 ;



to variable usage be very close to ‘zero’ OR ‘( E(a)/time(a) )’ {are 2 parameter} but the result are wrong :frowning: and all usage are between 0 and 0.01 !!

i know i can use binary variable but i have to use NLP solver.

any new advice or solution??


tanks you in advance









On Friday, November 14, 2014 11:56:12 PM UTC+3:30, Trish Gillett wrote:

So you mean that X can be either in (-inf, 0.1) or (2, inf)?

For starters, the strict inequalities are a problem. See Arne’s response from this post from a few months ago: https://groups.google.com/d/msg/gamsworld/l3Vkkss6cQQ/ofAZR-vMSQMJ

If you can settle for non-strict inequality, like X >= a and X = 0) and when x >= b (because x-a >= 0 and b-x 2 and X<0.1

How should i write this boundary in GAMS equations?

Thanks for your help in advance!

Azad

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4

Hi Azad,

I’m not sure I understand you, but here are a few things you can check.

Your constraint
(usage(n,a,h)-0.01 )* ((E(a)/time(a))- usage(n,a,h) ) =l= 0
will be satisfied in two cases:
Case 1: usage(n,a,h) = 0.01 AND usage(n,a,h) >= E(a)/time(a)

Idea #1) Double check that you definitely have E(a)/time(a) >= 0.01 in your problems.

Together with the rest of the code you include, each usage(n,a,h) has two possible ranges: [0, 0.01] and [E(a)/time(a), E(a)/time(a) + 0.2].
The reason this is important is because if you accidentally had E(a)/time(a) = a and X = b" like I described in the rest of the message. It looks like you understood me correctly despite this, thankfully.

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5

Tanks a lot dear Trish

based on your advice i write a new version of my code but it not work very well with solver you mentioned so i attach both version of my code

would you or any other help me about it

which solver i should use ? and is there any problem in my codes?
because as far i know all of three constrains i used are mathematically correct!!

thank you in advance,
your helps mean a lot to me

Azad




On Friday, November 14, 2014 5:45:49 PM UTC+3:30, Azad Mirzaiee wrote:

Hi

I have serious problem with defining a variable NOT to be between two number

for example X>2 and X<0.1

How should i write this boundary in GAMS equations?

Thanks for your help in advance!

Azad

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binary4help5.gms (24.1 KB)
NLP4help5.gms (24 KB)