How to avoid multiplication of two or more variables

GAMS
1

Hello All,


How can avoid multiplying two variables in MINLP like;

Eq1(c.l)… p =e= sum((j,s), beta(j,s))
Eq2(s,j,c,l)… q =e= sum(r, x(r,s,j,c,l))
mflow(c.l)… p * q =l= sum(j, alpha(c,j)* y(j,c,l)



where
y(j,c,l) is binary variable
x(r,s,j,c,l) is positive variable
beta & alpha are parameters

This set of eq definition gives in-feasible soln.

Any suggestion?

–
THANKS & REGARDS,

(AQEEL A. BAZMI)

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2

Hi Aqeel,

It seems your equations are linear. However, the formulation is a bit confusing. If you try to formulate the mflow (c,l) as
sum((j,s), beta(j,s)) sum(r, x(r,s,j,c,l)) =l= sum(j, alpha(c,j) y(j,c,l))
you will clearly see the problem. The indices of the RHS and LHS of the equation don’t match.
Try to formulate the equation correctly making sure both sides have equal indices (for e.g (c,l)).

Hope this helps!


On Tue, Nov 22, 2011 at 2:21 AM, AQEEL AHMED BAZMI wrote:

Hello All,


How can avoid multiplying two variables in MINLP like;

Eq1(c.l)… p =e= sum((j,s), beta(j,s))
Eq2(s,j,c,l)… q =e= sum(r, x(r,s,j,c,l))
mflow(c.l)… p * q =l= sum(j, alpha(c,j)* y(j,c,l)



where
y(j,c,l) is binary variable
x(r,s,j,c,l) is positive variable
beta & alpha are parameters

This set of eq definition gives in-feasible soln.

Any suggestion?

–
THANKS & REGARDS,

(AQEEL A. BAZMI)

\

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