Originally posted by: SystemAdmin

[Mengue said:]

Hi,

I want to know if the constraint line can be write in 2 (or more) lines.

Example:

Maximize
x1 + x2 + x3 + ...
+ x1001 + 1002 + 1003

Subject To
x1 + x2 + x3 + ...
+ x1001 + 1002 + 1003 <= 500<br />
End

Thanks!

Leandro Mengue


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#DecisionOptimization

Originally posted by: SystemAdmin

[shaon said:]

[quote author=Mengue link=topic=1391.msg3863#msg3863 date=1254073703]
Hi,

I want to know if the constraint line can be write in 2 (or more) lines.

Example:

Maximize
x1 + x2 + x3 + ...
+ x1001 + 1002 + 1003

Subject To
x1 + x2 + x3 + ...
+ x1001 + 1002 + 1003 <= 500<br />
End

Thanks!

Leandro Mengue




I think you need not care about this problem when creating the LP file. You just need to write a new contratint in a new line. Suppose you use c program to create this file, you just need to switch to a new line uising "\n" in fprintf. 
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#DecisionOptimization

Originally posted by: SystemAdmin

[Mengue said:]

Ok, so I understand that CPLEX will recognize that the end of constraint will be the line that has "<=", and that the next line is a new constraint, correct?<br />
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Originally posted by: SystemAdmin

[Mengue said:]

To be more especific: my contraint have a big length (+/- 5000 characters) like:

x1 + x2 + x3 + ... + x1001 + x1002 <= 500<br />
Remember that the line have a maximun lenght of 560 characters...

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#DecisionOptimization

Originally posted by: SystemAdmin

[shaon said:]

[quote author=Mengue link=topic=1391.msg3867#msg3867 date=1254076205]
To be more especific: my contraint have a big length (+/- 5000 characters) like:

x1 + x2 + x3 + ... + x1001 + x1002 <= 500<br />
Remember that the line have a maximun lenght of 560 characters...



In my experience, I also have many variables in each constraint. When creating the .LP file, I just enumerated each variable and then added "<= a" and switched to next line. I never cared about the maximum length. I still do not know the maximum length you mentioned.
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Originally posted by: SystemAdmin

[Mengue said:]

I see in the manual:

"The maximum length of any line of input is 560" -> from "ILOG CPLEX 10.0 File Formats" at "LP File Format"

But, if I understand, you have a constraint line with lenght bugger thar 560, correct? And it works?

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#DecisionOptimization

Originally posted by: SystemAdmin

[achterberg said:]

You can use as many lines as you want for the objective function and each constraint. In this regard, a newline '\n' is just treated as a space ' ' in the parser. Of course, you should not break variable names or numbers ;)

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