gams:formulate_logical_expressions_in_equations

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gams:formulate_logical_expressions_in_equations [2008/09/23 12:18] support |
gams:formulate_logical_expressions_in_equations [2008/09/25 17:00] support |
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For example, if you have a logical expression ''i=1 <=> a > b'' then you can reformulate this as | For example, if you have a logical expression ''i=1 <=> a > b'' then you can reformulate this as | ||

- | ''a %%<=%% b + bigM*i'' | + | ''a %%<=%% b + bigM * i'' |

- | ''a > b - bigM*(1-i)'' | + | ''a > b - bigM * (1-i)'' |

Try to evaluate: If ''i=1'' then the first constraint will not be effective if ''bigM'' is big enough while the second equation will read ''a>b''. If ''i=0'', the first constraint ensures ''a<=b'' while the second will | Try to evaluate: If ''i=1'' then the first constraint will not be effective if ''bigM'' is big enough while the second equation will read ''a>b''. If ''i=0'', the first constraint ensures ''a<=b'' while the second will |

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gams/formulate_logical_expressions_in_equations.txt ยท Last modified: 2013/08/05 10:00 by support