Dimod Conversion

These classes handle conversion between dwave-hybrid Runnable classes and dimod samplers.

Classes

class HybridSampler(workflow)

Produces a dimod.Sampler from a hybrid.Runnable-based sampler.

Parameters:

workflow (Runnable) – Hybrid workflow, likely composed, that accepts a binary quadratic model in the input state and produces sample(s) in the output state.

Example

This example produces a dimod sampler from TabuProblemSampler and uses its sample_ising mixin to solve a simple Ising problem.

>>> hybrid_sampler = TabuProblemSampler()
>>> dimod_sampler = HybridSampler(hybrid_sampler)
>>> solution = dimod_sampler.sample_ising({}, {'ab': 0.5, 'bc': 0.5, 'ca': 0.5})
>>> solution.first.energy
-0.5

class HybridRunnable(sampler, fields, **sample_kwargs)

Produces a hybrid.Runnable from a dimod.Sampler (dual of HybridSampler).

The runnable samples from a problem defined in a state field named fields[0] and populates the state field referred to by fields[1].

Parameters:

• sampler (dimod.Sampler) – dimod-compatible sampler which is run on every iteration of the runnable.

• fields (tuple(str, str)) – Input and output state field names.

• **sample_kwargs (dict) – Sampler-specific parameters passed to sampler on every call.

Example

This example creates a Runnable from dimod sampler TabuSampler, runs it on an Ising model, and finds the lowest energy.

>>> from dwave.samplers import TabuSampler
>>> import dimod
>>> bqm = dimod.BinaryQuadraticModel.from_ising({}, {'ab': 0.5, 'bc': 0.5, 'ca': 0.5})
>>> runnable = HybridRunnable(TabuSampler(), fields=('subproblem', 'subsamples'), timeout=100)
>>> state0 = State(subproblem=bqm, subsamples=SampleSet.from_samples_bqm(min_sample(bqm), bqm))
>>> state = runnable.run(state0)
>>> state.result()['subsamples'].first.energy     
-0.5

class HybridProblemRunnable(sampler, **sample_kwargs)

Produces a hybrid.Runnable from a dimod.Sampler (dual of HybridSampler).

The runnable that samples from state.problem and populates state.samples.

See an example in hybrid.core.HybridRunnable. An example of the duality with HybridSampler is:

HybridProblemRunnable(HybridSampler(TabuProblemSampler())) == TabuProblemSampler()

class HybridSubproblemRunnable(sampler, **sample_kwargs)

Produces a hybrid.Runnable from a dimod.Sampler (dual of HybridSampler).

The runnable that samples from state.subproblem and populates state.subsamples.

See an example in hybrid.core.HybridRunnable.