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xpress.Or

xpress.Or

Purpose

Returns a logical OR of two or more binary variables or expressions.


Synopsis
xpress.Or(variables)
Argument
variables 
A list/array of binary variables or binary expressions
Example
The following example shows how to use or 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.Or(x[1:]))

# Forces the logical OR between some logical expressions to
# be one, i.e., at least one of them must be one

p.addConstraint (xp.Or([x[1] & x[4], x[2] & x[1], x[3] & x[6]]) == 1)
Further information
1. For OR functions, all variables and expressions must be binary; an error will be generated otherwise.
2. A function call xpress.Or(x1,x2,...,xk) is equivalent to x1 or (x2 or (x3 or ... xk))...).
3. Note that since x1, x2, ..., xk, are binary variables, xpress.Or(x1,x2,...,xk) is equivalent to xpress.max(x1,x2,...,xk).
Related topics
problem.addgencons, problem.delgencons, problem.getgencons, xpress.And.

Parent Topic Reference Manual

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