Hi Luiz,

Thank you for your help, I would try different formulation.

Regards,

Dylan

åœ¨ 2013å¹´10æœˆ1æ—¥æ˜ŸæœŸäºŒUTC+8ä¸Šåˆ11æ—¶46åˆ†21ç§’ï¼Œluizcfså†™é“ï¼š

Dylan,

Given your extra information about the variables, I can’t think anything different from your initial

formulation

regards,

Luiz Carlos.

On Mon, Sep 30, 2013 at 4:38 AM, Dylan Lan wrote:

Hi Luiz,

Yes, both A(i) and B(j) are variables.

But A(i) - B(j) could be positive or negative.

Regards,

Dylan

åœ¨ 2013å¹´9æœˆ30æ—¥æ˜ŸæœŸä¸€UTC+8ä¸Šåˆ1æ—¶50åˆ†06ç§’ï¼Œluizcfså†™é“ï¼š

Hi, Dylan

Are both A(i) and B(j) variables?

In an affirmative case, can one of them be an upper bound for the other?

Regards,

Luiz Carlos.

On Sun, Sep 29, 2013 at 6:23 AM, Dylan Lan wrote:

Hi GAMS wolrd,

I have a problem in reformulating equation constraints in a disjunctive model by Big-M reformulation.

When reformulating equations constraints, the only way I know is to introduce two inequalities. for example:

A(i) = B(j) reformulated as:

A(i) - B(j) =l= M*( 1-x(i,j) ) ;

B(j) - A(i) =l= M*( 1-x(i,j) ) ;

sum( i$(ord(i)<=I), x(i,j) ) =e= 1 ;

where x is binary variable.

Is there any way to reduce the number of equation and inequalities I have to use in Big-M reformulation?

Regards,

Dylan

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