How do I set the initial value of an MVar?

Answered

Matthew Greenberg

June 13, 2022 18:31

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If I'm reading the docs correctly, MVars don't have a Start attribute. Is there an ergonomic way to set their initial values? Do I have to loop over the constituent Vars? Working with the Python version.

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 16, 2025 23:34

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  Jaromił Najman

  • Gurobi Staff

  June 14, 2022 07:02

  One way of setting the Start attribute for MVar objects is

  import gurobipy as gp
  import numpy as np
  
  m = gp.Model()
  
  x = m.addMVar(2)
  A = np.random.rand(2,2)
  
  m.addConstr(A @ x <= 1)
  
  start = [0,1]
  x.Start = start
  m.update()
  print(x.Start)

  You could alternatively use the tolist() method and assign each Start value one by one. You could also use a solution file, see How do I use MIP starts?

  Best regards, 
  Jaromił

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