netket.hilbert.DiscreteHilbert#

class netket.hilbert.DiscreteHilbert#

Bases: netket.hilbert.AbstractHilbert

Abstract class for an hilbert space defined on a lattice.

This class defines the common interface that can be used to interact with hilbert spaces on lattices.

Inheritance

__init__(shape)[source]#

Initializes a discrete Hilbert space with a basis of given shape.

Parameters: shape (Tuple[int, ...]) – The local dimension of the Hilbert space for each degree of freedom.

Attributes

is_finite#

Whether the local hilbert space is finite.

Return type: bool

is_indexable#

Whether the space can be indexed with an integer

Return type: bool

n_states#

The total dimension of the many-body Hilbert space. Throws an exception iff the space is not indexable.

Return type: int

shape#

The size of the hilbert space on every site.

Return type: Tuple[int, ...]

size#

The number number of degrees of freedom in the basis of this Hilbert space.

Return type: int

Methods

all_states(out=None)[source]#

Returns all valid states of the Hilbert space.

Throws an exception if the space is not indexable.

Parameters: out (Optional[ndarray]) – an optional pre-allocated output array
Return type: ndarray
Returns: A (n_states x size) batch of states. this corresponds to the pre-allocated array if it was passed.

numbers_to_states(numbers, out=None)[source]#

Returns the quantum numbers corresponding to the n-th basis state for input n. n is an array of integer indices such that numbers[k]=Index(states[k]). Throws an exception iff the space is not indexable.

Parameters

numbers (numpy.array) – Batch of input numbers to be converted into arrays of quantum numbers.
out (Optional[ndarray]) – Optional Array of quantum numbers corresponding to numbers.

Return type

ndarray

ptrace(sites)#

Returns the hilbert space without the selected sites.

Not all hilbert spaces support this operation.

Parameters: sites (Union[int, Iterable]) – a site or list of sites to trace away
Return type: AbstractHilbert
Returns: The partially-traced hilbert space. The type of the resulting hilbert space might be different from the starting one.

random_state(key=None, size=None, dtype=<class 'numpy.float32'>)#

Generates either a single or a batch of uniformly distributed random states. Runs as random_state(self, key, size=None, dtype=np.float32) by default.

Parameters

key – rng state from a jax-style functional generator.
size (Optional[int]) – If provided, returns a batch of configurations of the form (size, N) if size is an integer or (*size, N) if it is a tuple and where \(N\) is the Hilbert space size. By default, a single random configuration with shape (#,) is returned.
dtype – DType of the resulting vector.

Return type

Array

Returns

A state or batch of states sampled from the uniform distribution on the hilbert space.

Example

>>> import netket, jax
>>> hi = netket.hilbert.Qubit(N=2)
>>> k1, k2 = jax.random.split(jax.random.PRNGKey(1))
>>> print(hi.random_state(key=k1))
[1. 0.]
>>> print(hi.random_state(key=k2, size=2))
[[0. 0.]
 [0. 1.]]

size_at_index(i)[source]#

Size of the local degrees of freedom for the i-th variable.

Parameters: i (int) – The index of the desired site
Return type: int
Returns: The number of degrees of freedom at that site

states()[source]#

Returns an iterator over all valid configurations of the Hilbert space. Throws an exception iff the space is not indexable. Iterating over all states with this method is typically inefficient, and `all_states` should be preferred.

Return type: Iterator[ndarray]

states_at_index(i)[source]#

A list of discrete local quantum numbers at the site i. If the local states are infinitely many, None is returned.

Parameters: i (int) – The index of the desired site.
Return type: Optional[List[float]]
Returns: A list of values or None if there are infinitely many.

states_to_local_indices(x)[source]#

Returns a tensor with the same shape of x, where all local values are converted to indices in the range 0…self.shape[i]. This function is guaranteed to be jax-jittable.

For the Fock space this returns x, but for other hilbert spaces such as Spin this returns an array of indices.

NOTE: This function is experimental. Use at your own risk.

Parameters: x (Union[ndarray, DeviceArray, Tracer]) – a tensor containing samples from this hilbert space
Returns: a tensor containing integer indices into the local hilbert

states_to_numbers(states, out=None)[source]#

Returns the basis state number corresponding to given quantum states. The states are given in a batch, such that states[k] has shape (hilbert.size). Throws an exception iff the space is not indexable.

Parameters

states (ndarray) – Batch of states to be converted into the corresponding integers.
out (Optional[ndarray]) – Array of integers such that out[k]=Index(states[k]). If None, memory is allocated.

Returns

Array of integers corresponding to out.

Return type

numpy.darray