change from default noise tuple to None

horqrux/apply.py

@@ -141,7 +141,7 @@ def apply_operator_with_noise(
         if not is_density
         else apply_operator_dm(state, operator, target, control)
     )
-    if len(noise) == 0:
+    if noise is None:
         return state_gate
     else:
         kraus_ops = jnp.stack(tuple(reduce(add, tuple(n.kraus for n in noise))))
@@ -243,7 +243,8 @@ def apply_gate(
             operator, target, control = merge_operators(operator, target, control)
         noise = [g.noise for g in gate]
 
-    has_noise = len(reduce(add, noise)) > 0
+    # faster way to check has_noise
+    has_noise = noise != [None] * len(noise)
     if has_noise and not is_density:
         state = density_mat(state)
         is_density = True

horqrux/noise.py

@@ -7,7 +7,6 @@
 from jax.tree_util import register_pytree_node_class
 
 from .utils import (
-    ErrorProbabilities,
     StrEnum,
 )
 from .utils_noise import (
@@ -46,14 +45,14 @@ class NoiseType(StrEnum):
 @dataclass
 class NoiseInstance:
     type: NoiseType
-    error_probability: ErrorProbabilities
+    error_probability: tuple[float, ...] | float
 
     def __iter__(self) -> Iterable:
         return iter((self.kraus, self.error_probability))
 
     def tree_flatten(
         self,
-    ) -> tuple[tuple, tuple[NoiseType, ErrorProbabilities]]:
+    ) -> tuple[tuple, tuple[NoiseType, tuple[float, ...] | float]]:
         children = ()
         aux_data = (self.type, self.error_probability)
         return (children, aux_data)
@@ -71,4 +70,4 @@ def __repr__(self) -> str:
         return self.type + f"(p={self.error_probability})"
 
 
-NoiseProtocol = tuple[NoiseInstance, ...]
+NoiseProtocol = tuple[NoiseInstance, ...] | None

horqrux/parametric.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any, Iterable
 
 import jax.numpy as jnp
@@ -31,7 +31,7 @@ class Parametric(Primitive):
     generator_name: str
     target: QubitSupport
     control: QubitSupport
-    noise: NoiseProtocol = field(default_factory=tuple)
+    noise: NoiseProtocol = None
     param: str | float = ""
 
     def __post_init__(self) -> None:
@@ -84,7 +84,7 @@ def RX(
     param: float | str,
     target: TargetQubits,
     control: ControlQubits = (None,),
-    noise: NoiseProtocol = tuple(),
+    noise: NoiseProtocol = None,
 ) -> Parametric:
     """RX gate.
 
@@ -104,7 +104,7 @@ def RY(
     param: float | str,
     target: TargetQubits,
     control: ControlQubits = (None,),
-    noise: NoiseProtocol = tuple(),
+    noise: NoiseProtocol = None,
 ) -> Parametric:
     """RY gate.
 
@@ -124,7 +124,7 @@ def RZ(
     param: float | str,
     target: TargetQubits,
     control: ControlQubits = (None,),
-    noise: NoiseProtocol = tuple(),
+    noise: NoiseProtocol = None,
 ) -> Parametric:
     """RZ gate.
 
@@ -161,7 +161,7 @@ def PHASE(
     param: float,
     target: TargetQubits,
     control: ControlQubits = (None,),
-    noise: NoiseProtocol = tuple(),
+    noise: NoiseProtocol = None,
 ) -> Parametric:
     """Phase gate.
 

horqrux/primitive.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any, Iterable, Union
 
 import numpy as np
@@ -28,7 +28,7 @@ class Primitive:
     generator_name: str
     target: QubitSupport
     control: QubitSupport
-    noise: NoiseProtocol = field(default_factory=tuple)
+    noise: NoiseProtocol | None = None
 
     @staticmethod
     def parse_idx(
@@ -85,7 +85,7 @@ def __repr__(self) -> str:
 
 
 def I(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """Identity / I gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -104,7 +104,7 @@ def I(
 
 
 def X(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """X gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -127,7 +127,7 @@ def X(
 
 
 def Y(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """Y gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -147,7 +147,7 @@ def Y(
 
 
 def Z(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """Z gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -167,7 +167,7 @@ def Z(
 
 
 def H(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """H/ Hadamard gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -186,7 +186,7 @@ def H(
 
 
 def S(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """S gate or constant phase gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -205,7 +205,7 @@ def S(
 
 
 def T(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """T gate. This function returns an instance of 'Primitive' and does *not* apply the gate.
     By providing tuple of ints to 'control', it turns into a controlled gate.
@@ -227,7 +227,7 @@ def T(
 
 
 def SWAP(
-    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = tuple()
+    target: TargetQubits, control: ControlQubits = (None,), noise: NoiseProtocol = None
 ) -> Primitive:
     """SWAP gate. By providing a control, it turns into a controlled gate (Fredkin gate),
        use None for no control qubits.

horqrux/utils.py

@@ -18,8 +18,6 @@
 QubitSupport = tuple[Any, ...]
 ControlQubits = tuple[Union[None, tuple[int, ...]], ...]
 TargetQubits = tuple[tuple[int, ...], ...]
-ErrorProbabilities = Union[tuple[float, ...], float]
-
 ATOL = 1e-014
 
 

horqrux/utils_noise.py

@@ -104,7 +104,7 @@ def PauliChannel(error_probability: tuple[float, ...]) -> tuple[Array, ...]:
             + pz Z \\rho Z^{\\dagger}
 
     Args:
-        error_probability (ErrorProbabilities): tuple containing probabilities
+        error_probability (tuple[float, ...] | float): tuple containing probabilities
             of X, Y, and Z errors.
 
     Raises:
@@ -224,7 +224,7 @@ def GeneralizedAmplitudeDamping(error_probability: tuple[float, ...]) -> tuple[A
         K3 = sqrt(1-p) * [[0, 0], [sqrt(rate), 0]]
 
     Args:
-        error_probability (ErrorProbabilities): The first float must be the probability
+        error_probability (tuple[float, ...] | float): The first float must be the probability
             of amplitude damping error, and the second float is the damping rate, indicating
             the probability of generalized amplitude damping.