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gams:formulate_a_constraint_with_a_condition [2007/08/10 10:51]
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gams:formulate_a_constraint_with_a_condition [2010/07/19 14:50]
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 ====== How do I formulate a constraint with a "<"​ condition? ====== ====== How do I formulate a constraint with a "<"​ condition? ======
  
-  * There is no difference between ''<''​ and ''<​=''​ for continuous variables when dealing with numerical algorithms. +In optimization,​ strict inequalities do not make sense. What is the solution 
-  * For discrete variables, the constraints mean exactly what they say. ''​=L=''​ means ''<​='',​ thus a constraint with an integer variable ''​=L= 9''​ means it can be less or equal to 9. If you want it to be less than 9, write the constraint as ''​=L= 8''​.+to the model 
 +<​code>​ 
 +min x, subject to x > 0 ? Is it 1.e-10 or 1.e-20 or something smaller. 
 +</​code>​ 
 +Optimization theory is usually concerned with bounded closed sets where closed means that the boundary is part of the feasible set. Thus there is no difference between ''<''​ and ''<​ =''​ for continuous variables when dealing with numerical algorithms. For discrete variables, the constraints mean exactly what they say. ''​=L=''​ means ''<​ ='',​ thus a constraint with an integer variable ''​=L= 9''​ means it can be less or equal to 9. If you want it to be less than 9, write the constraint as ''​=L= 8''​.
  
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