[Cmpl] help

[Mike Steglich]

Hello Pryanki,

I did not check the entire model. But your first group of constraints (e.g.  x[i,j] * R_lan[i,k] >= 10)  forces your model to be infeasible:

For the two cases for a x[i,j] we have the following results
1) x[i,j] = 0   ->   x[i,j] * R_lan[i,k] >= 10  -> False, because 0>=10 is wrong
2) x[i,j] = 1   ->   x[i,j] * R_lan[i,k] >= 10  -> True or False, because 1*  R_lan[i,k] >=10 is true if R_lan[i,k] >= 10 or false if R_lan[i,k] < 10

A better formulation could be:
R_lan[i,k] >= 10 * x[i,j] 

because:
1) x[i,j] = 0   ->  R_lan[i,k] >= 10 * x[i,j]  -> True, because R_lan[i,k] >=0 is true
2) x[i,j] = 1   ->  R_lan[i,k] >= 10 * x[i,j]  -> True, because R_lan[i,k] >=10 is true if R_lan[i,k] >= 10 or  if R_lan[i,k] < 10 then x[i,j] is forced to become 0


Cheers,

Mike


Am 17.09.2013 um 18:40 schrieb Priyanki Sharma:

> Hello ,
> 
> I have been trying to solve this cmpl code. It gives infeasible all the time. I don't understand why this is happening. I have attached the question in a word document and the cmpl code . I am trying to solve the first part of the question but there is something wrong with the first constraint called " con1". I just can't figure out what is going wrong. Its quite urgent. Could someone please help. I would really appreciate any help asap.
> 
> Thanks
> 
> Regards
> Priyanki
> <During the Second World War the Royal Air Force.docx><final test4.cmpl>_______________________________________________
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