An unofficial library to embed and send optimization (QUBO, Ising) problems to DWave System quantum annealing solvers. A native Dart equivalent to the [Ocean SDK][dwave_ocean_ref].

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

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

COMING SOON!

Sample using local simulator

import { Solver, Qubo } from 'qubo-embedder';

const qubo = new Qubo(2);
qubo.addEntry(0, 0, 2.0);
qubo.addEntry(1, 1, 2.0);
qubo.addEntry(0, 1, -2.0);

Solver.simulator().sampleQubo(qubo, 5).then(solutionRecord => {
    console.log(solutionRecord.toString());
});

Data structures

You can format your problems using built-in data types. These use mathjs 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 { Qubo } from 'qubo-embedder';

const qubo = new Qubo(2);

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

console.log(qubo.getEntry(0, 1)); // -2.0
console.log(qubo.toString()); // [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 { Qubo, Hamiltonian } from 'qubo-embedder';

const qubo = new Qubo(2);
qubo.addEntry(0, 0, 2.0);
qubo.addEntry(1, 1, 2.0);
qubo.addEntry(0, 1, -2.0);

const hamiltonian = Hamiltonian.fromQubo(qubo);

console.log(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 { SolutionVector } from 'qubo-embedder';

const solutionVector = SolutionVector.fromList([0, 1]);

console.log(solutionVector.vector); // [0, 1]
console.log(solutionVector.toString()); // [q0: 0, q1: 1]

SolutionRecord

Sampler store their solutions as entries in this record, which you can get by entries() and iterate over for solution details. When returned by a sampler, the entries are sorted by energy in ascending order.

import { Qubo, Solver, SolutionRecord } from 'qubo-embedder';

const qubo = new Qubo(2);
qubo.addEntry(0, 0, 2.0);
qubo.addEntry(1, 1, 2.0);
qubo.addEntry(0, 1, -2.0);

Solver.simulator().sampleQubo(qubo).then(solutionRecord => {
    for (const entry of solutionRecord.entries()) {
        console.log(`E=${entry.energy}\t${entry.solutionVector}\tx${entry.numOccurrences}`);
    } 
    //E=0     [q0: 0, q1: 0, ]        x1
    //E=2     [q0: 0, q1: 1, ]        x1

    console.log(solutionRecord.toString());
    //   energy       sample  occurrences
    //(1) 0   [q0: 0, q1: 0, ]        x1
    //(2) 2   [q0: 0, q1: 1, ]        x1
});