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gams:formulate_a_constraint_with_a_condition

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 gams:formulate_a_constraint_with_a_condition [2007/08/10 10:51]127.0.0.1 external edit gams:formulate_a_constraint_with_a_condition [2010/07/19 14:36]support 2010/07/19 14:50 support 2010/07/19 14:36 support 2007/08/10 10:51 external edit 2010/07/19 14:50 support 2010/07/19 14:36 support 2007/08/10 10:51 external edit Last revision Both sides next revision Line 1: Line 1: ====== 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. + ​ + Optimization theory is usually concerned with bounded closed sets where closed means that the boundary is part of the feasible set. Thus 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''​. 