20 lines
833 B
Mathematica
20 lines
833 B
Mathematica
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function x = true(x)
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% TRUE Constrains a variable to be positive
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%
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% TRUE(x) returns the constraint (x>=0.5). It is assumed that x is
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% binary. The reason (x>=0.5) is used instead of x==1 is that some big-M
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% modelling turns out to be less sensitive to numerical issues in this
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% form. Once the model enters the solver, it will be trivially presolved
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% anyway.
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%
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% For safety, it is advised to use the TRUE operator when working with
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% logic constraints, instead of relying on the automatic constraints used
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% by YALMIP (expression generated using AND and OR are automatically
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% assumed to be constrained to be true.
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%
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% (a|b) is automatically changed to (TRUE(a|b)). To constrain a to be true,
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% the user has to explicitely use (TRUE(a)).
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%
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% See also SDPVAR/FALSE, SDPVAR/AND, SDPVAR/OR, SDPVAR/NOT, BINVAR, BINARY
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x = (x>=.5);
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