qubo_embedder 0.1.0

An unofficial library to embed and send QUBO (quadratic unconstrained binary optimization) problems to DWave System quantum annealing solvers.

An unofficial library to embed and send QUBO (quadratic unconstrained binary optimization) problems to DWave System quantum annealing solvers. A native Dart equivalent to the Ocean SDK.

TABLE OF CONTENTS

• Usage
  • Send to remote DWave annealer solver
  • Sample using local simulator
• Data structures
  • Qubo
  • Hamiltonian
  • SolutionVector

---

Usage

Solving QUBO problems is handled by the Solver class which has different modes. Assuming you have your data prepared, it's relatively easy to get your solutions:

Send to remote DWave annealer solver

await Solver.dwave_sampler(
    token='[YOUR_API_TOKEN]',
    solver='Advantage_system5.1',
    ).sample(
        hamiltonian,
        record_length=5,
    )

This takes care of the minor-embedding, API calls etc. automatically.

Sample using local simulator

Solver.simulator().sample(
    hamiltonian,
    record_length=5,
)

Data structures

You can format your problems using built-in data types. These use the ml_linalg package internally to provide fast and efficient handling of linear algebra types and operations, especially in the Solver.simulator() solver.

Qubo

Add the coefficients of your QUBO-problems using the indices of the affected variables (beginning at 0).

import 'package:qubo_embedder/qubo_embedder.dart';

void main() {
    var qubo = Qubo(size: 2);

    qubo.addEntry(0, 0, value: 2.0);
    qubo.addEntry(1, 1, value: 2.0);
    qubo.addEntry(0, 1, value: -2.0);
    // qubo.addEntry(1, 0, value: 2.0) throws an InvalidOperationException

    print(qubo.getEntry(0, 1)); // -2.0
    print(qubo); // [qubits: 2] {(0, 0): 2.0, (0, 1): -2.0, (1, 1): 2.0}
}

Hamiltonian

If you're done, you can transform Qubo objects to Hamiltonian which the samplers take as an input.

import 'package:qubo_embedder/qubo_embedder.dart';

void main() {
    var hamiltonian = Hamiltonian.fromQubo(qubo);

    print(hamiltonian.matrix) // [[2.0, -2.0], [0.0, 2.0]]
}

SolutionVector

This type you seldom have to create for yourself, but is used by the solvers to return the solutions to a QUBO problem. A solution vector is immutable, but can be transformed into a regular list.

import 'package:qubo_embedder/qubo_embedder.dart';

void main() {
    var solutionVector = SolutionVector.fromList([0, 1]);

    print(solutionVector.vector); // [0, 1]
    print(solutionVector); // [q0: 0, q1: 1]
}