symmray.symmetries

Definitions of various symmetries.

Classes

Symmetry	Helper class that provides a standard way to create an ABC using
ZN	Helper class that provides a standard way to create an ABC using
Z2	Helper class that provides a standard way to create an ABC using
U1	Helper class that provides a standard way to create an ABC using
Z2Z2	Helper class that provides a standard way to create an ABC using
U1U1	Helper class that provides a standard way to create an ABC using

Functions

sign_scalar(charge[, dual])
sign_tuple(charge[, dual])
get_zn_symmetry_cls(→ type)	Get a ZN symmetry class.
get_symmetry(→ Symmetry)	Get a symmetry instance by name.
calc_phase_permutation(→ int)	Given sequence of parities and a permutation, compute the phase of the

Module Contents

class symmray.symmetries.Symmetry

Bases: abc.ABC

Helper class that provides a standard way to create an ABC using inheritance.

__slots__ = ()

abstractmethod valid(*charges)

Check if all charges are valid for the symmetry.

abstractmethod combine(*charges)

Combine / add charges according to the symmetry.

abstractmethod sign(charge, dual=True)

Negate a charge according to the symmetry and flag dual.

abstractmethod parity(charge)

Return the parity, 0 or 1, of a charge according to the symmetry.

abstractmethod random_charge(seed=None)

Return a random valid charge, for testing purposes.

__str__()

__eq__(other)

__hash__()

__repr__()

symmray.symmetries.sign_scalar(charge, dual=True)

symmray.symmetries.sign_tuple(charge, dual=True)

class symmray.symmetries.ZN

Bases: Symmetry

Helper class that provides a standard way to create an ABC using inheritance.

__slots__ = ('N',)

valid(*charges: int) → bool

Check if all charges are valid for the symmetry.

combine(*charges: int) → int

Combine / add charges according to the symmetry.

sign(charge: int, dual=True) → int

Negate a charge according to the symmetry and flag dual.

parity(charge: int) → int

Return the parity, 0 or 1, of a charge according to the symmetry.

random_charge(seed=None) → int

Return a random valid charge, for testing purposes.

__reduce__()

class symmray.symmetries.Z2

Bases: ZN

Helper class that provides a standard way to create an ABC using inheritance.

N = 2

sign(charge: int, dual=True) → int

Negate a charge according to the symmetry and flag dual.

symmray.symmetries.get_zn_symmetry_cls(N: int) → type

Get a ZN symmetry class.

class symmray.symmetries.U1

Bases: Symmetry

Helper class that provides a standard way to create an ABC using inheritance.

__slots__ = ()

valid(*charges: int) → bool

Check if all charges are valid for the symmetry.

combine(*charges: int) → int

Combine / add charges according to the symmetry.

sign(charge: int, dual=True) → int

Negate a charge according to the symmetry and flag dual.

parity(charge: int) → int

Return the parity, 0 or 1, of a charge according to the symmetry.

random_charge(seed=None) → int

Return a random valid charge, for testing purposes.

class symmray.symmetries.Z2Z2

Bases: Symmetry

Helper class that provides a standard way to create an ABC using inheritance.

__slots__ = ()

valid(*charges: tuple[int, int]) → bool

Check if all charges are valid for the symmetry.

combine(*charges: tuple[int, int]) → tuple[int, int]

Combine / add charges according to the symmetry.

sign(charge: tuple[int, int], dual=True) → tuple[int, int]

Negate a charge according to the symmetry and flag dual.

parity(charge: tuple[int, int]) → int

Return the parity, 0 or 1, of a charge according to the symmetry.

random_charge(seed=None) → tuple[int, int]

Return a random valid charge, for testing purposes.

class symmray.symmetries.U1U1

Bases: Symmetry

Helper class that provides a standard way to create an ABC using inheritance.

__slots__ = ()

valid(*charges: tuple[int, int]) → bool

Check if all charges are valid for the symmetry.

combine(*charges: tuple[int, int]) → tuple[int, int]

Combine / add charges according to the symmetry.

sign(charge: tuple[int, int], dual=True) → tuple[int, int]

Negate a charge according to the symmetry and flag dual.

parity(charge: tuple[int, int]) → int

Return the parity, 0 or 1, of a charge according to the symmetry.

random_charge(seed=None) → tuple[int, int]

Return a random valid charge, for testing purposes.

symmray.symmetries.get_symmetry(symmetry: str | Symmetry) → Symmetry

Get a symmetry instance by name.

Parameters:

symmetry (str or Symmetry) – The symmetry to get.

Returns:

The symmetry instance.

Return type:

Symmetry

symmray.symmetries.calc_phase_permutation(parities: tuple[int, Ellipsis], perm: tuple[int, Ellipsis] = None) → int

Given sequence of parities and a permutation, compute the phase of the permutation acting on the odd charges. I.e. whether the number of swaps of odd sectors is even or odd.

Parameters:

• parities (tuple of int) – The parities of the sectors.

• perm (tuple of int, optional) – The permutation of axes, by default None, which flips all axes.

Returns:

The phase of the permutation, either 1 or -1.

Return type:

int