# netket.sampler.rules.HamiltonianRule#

class netket.sampler.rules.HamiltonianRule#

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.

Inheritance
Attributes
operator: netket.operator.AbstractOperator#
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 split.

It should return an immutable data structure.

Parameters
• sampler – The Metropolis sampler.

• machine – A Flax module with the forward pass of the log-pdf.

• params – The PyTree of parameters of the model.

• key – A Jax PRNGKey.

Returns

An optional state.

random_state(sampler, machine, params, sampler_state, key)#

Generates a random state compatible with this rule.

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

Parameters

“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.

The default implementation returns the current rule_state without modifying it.

Parameters
Return type
Returns

A reset state of the rule. This returns the same type of rule_state() and might be None.

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

Proposes a new configuration set of configurations $sigma’$ starting from the current chain configurations $$\sigma$$.

The new configurations $$\sigma'$$ should be a matrix with the same dimension as $$\sigma$$.

This function should return a tuple. where the first element are the new configurations $sigma’$ and the second element is either None or an array of length σ.shape[0] containing an optional log-correction factor. The correction factor should be non-zero when the transition rule is non-symmetrical.

Parameters
• sampler – The Metropolis sampler.

• machine – A Flax module with the forward pass of the log-pdf.

• params – The PyTree of parameters of the model.

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

• key – A Jax PRNGKey to use to generate new random configurations.

• σ – The current configurations stored in a 2D matrix.

Returns

A tuple containing the new configurations $$\sigma'$$ and the optional vector of log corrections to the transition probability.