Create a problem with general constraints that use operator abs
Create a simple problem using the modelling methods abs for creating general constraints.
Further explanation of this example: 'Xpress Python Reference Manual'
# Example using general constraints - the abs() operator # # (C) Fair Isaac Corp., 1983-2020 import xpress as xp # Here we use the abs operator of the Python interface to create a new # optimization problem. # Find the point that minimizes the l-1 norm within a given polytope, # i.e. the sum of the absolute values of the coordinates of a point in # a polytope. p = xp.problem() # Read data from a problem of MIPLIB 2017 p.read('pk1.mps.gz') # Retrieve all variables of the original problem x = p.getVariable() # Change objective function to the l-1 norm of the variable vector, to # be minimized. p.setObjective (xp.Sum(xp.abs(v) for v in x)) # Set time limit to 20 seconds p.controls.maxtime = -20 p.solve() print("solution:", p.getSolution())
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