Initializing help system before first use

problem.getRedCosts

Purpose
Used to obtain the reduced costs associated with the incumbent solution during or after optimization with problem.optimize, problem.mipoptimize, problem.lpoptimize or problem.nlpoptimize.
Synopsis
djs = problem.getRedCosts(*variables)
Argument
variables 
(optional) variable objects whose reduced costs will be returned. If none is provided, a list of reduced costs of all variables in the problem will be returned.
Return value
djs 
A list of reduced cost values if *variables contains more than one variable object or is not provided, a single reduced cost value otherwise.
Example 
import xpress as xp
import numpy as np
p = xp.problem()
x = p.addVariables(10, name='y')  # creates 10 variables named 'y(0)', 'y(1)', etc.
A = np.random.random((5,10))
b = np.random.random(5)
constr = xp.Dot(A,x) >= b
p.addConstraint(constr)
p.setObjective(xp.Sum(x))
p.optimize()
print("Reduced costs of first two variables:", p.getRedCosts(x[:2]))
print("Reduced costs of last two variables:", p.getRedCosts('y(8)', 'y(9)'))
Related topics
problem.optimize, problem.getSolution, problem.getDuals, problem.getSlacks.

Parent Topic Xpress problem methods

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