xpress.And
xpress.And |
Purpose
Returns a logical AND of two or more binary variables or expressions.
Synopsis
xpress.And(variables)
Argument
|
variables
|
A list/array of binary variables or binary expressions
|
Example
The following example shows how to use
and to model various logical constraints:
N = 10 x = xp.vars(N, vartype=xp.binary) # Creates N binary variables c = [1, 4, 7, 3, 5, 7, 8, 4, 4, 9] p = xp.problem(x) # Creates a problem with x, y # Sets a linear objective p.setObjective (xp.Sum(c[i] * x[i] for i in range(N)) # Linear constraint p.addConstraint (xp.Sum(x) <= 6) # Constrains the first x variable to be the conjunction of all other x's p.addConstraint (x[0] == xp.And(x[1:])) # Forces the logical AND between some logical expressions to # be zero, i.e., at least one of them must be zero p.addConstraint (xp.And([x[1] | x[4], x[2] | x[1], x[3] | x[6]]) == 0)
Further information
1. For
AND functions, all variables and expressions must be binary; an error will be generated otherwise.
2. A function call
xpress.And(x1,x2,...,xk) is equivalent to
x1 and (x2 and (x3 and ... xk))...).
3. Note that since
x1,
x2, ...,
xk, are binary variables,
xpress.And(x1,x2,...,xk) is equivalent to
xpress.min(x1,x2,...,xk).
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