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Is this sort of a constraint implementable in Python?

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  Is this sort of a constraint implementable in Python? varun7rs@gmail.com - 2014-06-10 02:12 -0700
    Re: Is this sort of a constraint implementable in Python? Gary Herron <gary.herron@islandtraining.com> - 2014-06-10 13:06 -0700

#73079 — Is this sort of a constraint implementable in Python?

Hello Everyone,

I'm working on a python code to input matrices into CPLEX solver. I have most of my code running fine but as of now, I don't know how to express this constraint. My objective is to minimize the number of nodes. I have got one of the weirdest looking constraints which I don't know how to express in Python because python basically takes matrices and inputs them into cplex. My constraint is as below. This was what I wrote in AMPL

minimize phy_nodes: sum {w in PHY_NODES} x_ns[w] ;

s.t. Phy_nodes_Eq{w in PHY_NODES, dns in DEMAND}:
x_ns[w] = 1 ==> x_SGW[dns, w] + x_PGW[dns, w] + x_MME[dns, w] + x_IMS[dns, w] + x_PoP[dns, w] >= 1
else x_SGW[dns, w] + x_PGW[dns, w] + x_MME[dns, w] + x_IMS[dns, w] + x_PoP[dns, w] = 0;
Could you help me fix this problem? 

Thank You

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#73121

On 06/10/2014 02:12 AM, varun7rs@gmail.com wrote:
> Hello Everyone,
>
> I'm working on a python code to input matrices into CPLEX solver. I have most of my code running fine but as of now, I don't know how to express this constraint. My objective is to minimize the number of nodes. I have got one of the weirdest looking constraints which I don't know how to express in Python because python basically takes matrices and inputs them into cplex. My constraint is as below. This was what I wrote in AMPL
>
> minimize phy_nodes: sum {w in PHY_NODES} x_ns[w] ;
>
> s.t. Phy_nodes_Eq{w in PHY_NODES, dns in DEMAND}:
> x_ns[w] = 1 ==> x_SGW[dns, w] + x_PGW[dns, w] + x_MME[dns, w] + x_IMS[dns, w] + x_PoP[dns, w] >= 1
> else x_SGW[dns, w] + x_PGW[dns, w] + x_MME[dns, w] + x_IMS[dns, w] + x_PoP[dns, w] = 0;
> Could you help me fix this problem?
>
> Thank You

This is more a CPLEX question than a Python question.  (Or rather a 
question about some Python/Cplex interface.) Do you have access to any 
kind of a CPLEX forum or a Cplex-via-Python forum?  I think that's much 
more likely to get you an answer.

Luck,
Gary Herron

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