# netket.sampler.rules.HamiltonianRule¶

class netket.sampler.rules.HamiltonianRule(operator)[source]

Bases: netket.sampler.metropolis.MetropolisRule

Rule proposing moves according to the terms in an operator.

In this case, the transition matrix is taken to be:

$T( \mathbf{s} \rightarrow \mathbf{s}^\prime) = \frac{1}{\mathcal{N}(\mathbf{s})}\theta(|H_{\mathbf{s},\mathbf{s}^\prime}|),$

This rule only works on CPU! If you want to use it on GPU, you must use the numpy variant netket.sampler.rules.HamiltonianRuleNumpy together with the numpy metropolis sampler netket.sampler.MetropolisSamplerNumpy.

Methods
init_state(sampler, machine, params, key)[source]

Initialises the optional internal state of the Metropolis Sampler Transition Rule.

The provided key is unique and does not need to be splitted. It should return an immutable datastructure.

Parameters
• sampler – The Metropolis sampler

• machine – The forward evaluation function of the model, accepting PyTrees of parameters and inputs.

• params – The dict of variables needed to evaluate the model.

• key – A Jax PRNGKey rng state.

Returns

An Optional State.

random_state(sampler, machine, parameters, state, key)

Generates a random state compatible with this rule.

By default this calls netket.hilbert.random.random_state().

Parameters
• sampler (Sampler) – the sampler

• machine (Callable) – the function to evaluate the model

• parameters (Any) – the parameters of the model

• state (SamplerState) – the current sampler state

• key (Any) – the PRNGKey to use to generate the random state

replace(**updates)

“Returns a new object replacing the specified fields with new values.

reset(sampler, machine, params, sampler_state)

Resets the internal state of the Metropolis Sampler Transition Rule.

Parameters
• sampler (Sampler) – The Metropolis sampler

• machine (Callable) – The forward evaluation function of the model, accepting PyTrees of parameters and inputs.

• params (Any) – The dict of variables needed to evaluate the model.

• sampler_state (SamplerState) – The current state of the sampler. Should not modify it.

Return type
Returns

A new, resetted, state of the rule. This returns the same type of sampler_state.rule_state() and might be None.

transition(sampler, machine, parameters, state, key, σ)[source]