optimization-problem.md

author	description	ms.author	ms.date	ms.service	ms.subservice	ms.topic	title	uid
george-moussa	Reference for azure.quantum.optimization.Problem	georgenm	02/01/2021	azure-quantum	optimization	reference	Quantum optimization problem	microsoft.quantum.optimization.problem

Quantum optimization problem

Problem

from azure.quantum.optimization import Problem

Constructor

To create a Problem object, you specify the following information:

• name: A friendly name for your problem. No uniqueness constraints.
• [optional] terms: A list of Term objects to add to the problem.
• [optional] problem_type: The type of problem. Must be either ProblemType.ising or ProblemType.pubo. Default is ProblemType.ising.

terms = [
    Term(c=-9, indices=[0]),
    Term(c=-3, indices=[1,0]),
    Term(c=5, indices=[2,0])
]

problem = Problem(name="My Difficult Problem", terms=terms)

Problem.add_term

Adds a single term to the problem. It takes a coefficient for the term and the indices of variables that appear in the term.

coefficient = 0.13
problem.add_term(c=coefficient, indices=[2,0])

Problem.add_terms

Adds multiple terms to the problem using a list of Terms.

problem.add_terms([
    Term(c=-9, indices=[0]),
    Term(c=-3, indices=[1,0]),
    Term(c=5, indices=[2,0]),
    Term(c=9, indices=[2,1]),
    Term(c=2, indices=[3,0]),
    Term(c=-4, indices=[3,1]),
    Term(c=4, indices=[3,2])
])

Problem.serialize

Serializes a problem to a json string.

problem = Problem("My Problem", [Term(c=1, indices=[0,1])])
problem.serialize()

> {"cost_function": {"version": "1.0", "type": "ising", "terms": [{"c": 1, "ids": [0, 1]}]}}

Problem.upload

Problem data can be explicitly uploaded to an Azure storage account using its upload method that receives as a parameter the Workspace instance:

problem.upload(workspace=workspace)

Once a problem is explicitly uploaded, it will not be automatically uploaded during submission unless its terms change.