Merge pull request #42 from ColibrITD-SAS/feat-delayed-imports

Feature: shorter import times by delaying some auxiliary imports

Author: Henri-ColibrITD

mpqp/core/circuit.py

@@ -2,17 +2,17 @@
 
 from copy import deepcopy
 from numbers import Complex
-from typing import Iterable, Optional, Sequence, Type, Union
+from typing import TYPE_CHECKING, Iterable, Optional, Sequence, Type, Union
+
+if TYPE_CHECKING:
+    from qat.core.wrappers.circuit import Circuit as myQLM_Circuit
+    from cirq.circuits.circuit import Circuit as cirq_Circuit
+    from braket.circuits import Circuit as braket_Circuit
+    from qiskit.circuit import QuantumCircuit
 
 import numpy as np
 import numpy.typing as npt
-from braket.circuits import Circuit as braket_Circuit
-from cirq.circuits.circuit import Circuit as cirq_Circuit
 from matplotlib.figure import Figure
-from qat.core.wrappers.circuit import Circuit as myQLM_Circuit
-from qiskit.circuit import Operation, QuantumCircuit
-from qiskit.circuit.quantumcircuit import CircuitInstruction
-from qiskit.quantum_info import Operator
 from sympy import Basic, Expr
 from typeguard import TypeCheckError, typechecked
 
@@ -626,6 +626,10 @@ def to_other_language(self, language: Language = Language.QISKIT) -> Union[
         """
 
         if language == Language.QISKIT:
+            from qiskit.circuit import Operation, QuantumCircuit
+            from qiskit.circuit.quantumcircuit import CircuitInstruction
+            from qiskit.quantum_info import Operator
+
             # to avoid defining twice the same parameter, we keep trace of the
             # added parameters, and we use those instead of new ones when they
             # are used more than once
@@ -642,15 +646,16 @@ def to_other_language(self, language: Language = Language.QISKIT) -> Union[
                 qiskit_inst = instruction.to_other_language(
                     Language.QISKIT, qiskit_parameters
                 )
-                assert (
-                    isinstance(qiskit_inst, CircuitInstruction)
-                    or isinstance(qiskit_inst, Operation)
-                    or isinstance(qiskit_inst, Operator)
-                )
+                if TYPE_CHECKING:
+                    assert (
+                        isinstance(qiskit_inst, CircuitInstruction)
+                        or isinstance(qiskit_inst, Operation)
+                        or isinstance(qiskit_inst, Operator)
+                    )
                 cargs = []
 
                 if isinstance(instruction, CustomGate):
-                    new_circ.unitary(
+                    new_circ.unitary(  # pyright: ignore[reportAttributeAccessIssue]
                         instruction.to_other_language(),
                         instruction.targets,
                         instruction.label,
@@ -674,8 +679,9 @@ def to_other_language(self, language: Language = Language.QISKIT) -> Union[
                     qargs = range(instruction.size)
                 else:
                     raise ValueError(f"Instruction not handled: {instruction}")
-                assert not isinstance(qiskit_inst, Operator)
 
+                if TYPE_CHECKING:
+                    assert not isinstance(qiskit_inst, Operator)
                 new_circ.append(
                     qiskit_inst,
                     qargs,
@@ -734,7 +740,8 @@ def to_qasm2(self) -> str:
         qiskit_circ = self.subs({}, remove_symbolic=True).to_other_language(
             Language.QISKIT
         )
-        assert isinstance(qiskit_circ, QuantumCircuit)
+        if TYPE_CHECKING:
+            assert isinstance(qiskit_circ, QuantumCircuit)
         qasm = qiskit_circ.qasm()
         assert qasm is not None
         return qasm

mpqp/core/instruction/barrier.py

@@ -2,12 +2,13 @@
 removed because it could have a negative impact on the execution speed of the
 circuit (since it artificially increases the depth)."""
 
-from typing import Optional
-from qiskit.circuit.library import Barrier as QiskitBarrier
+from typing import TYPE_CHECKING, Optional
 
-from qiskit.circuit import Parameter
+if TYPE_CHECKING:
+    from qiskit.circuit import Parameter
 
 from mpqp.core.languages import Language
+
 from .instruction import Instruction
 
 
@@ -22,7 +23,9 @@ def __init__(self):
     def to_other_language(
         self,
         language: Language = Language.QISKIT,
-        qiskit_parameters: Optional[set[Parameter]] = None,
+        qiskit_parameters: Optional[set["Parameter"]] = None,
     ):
         if language == Language.QISKIT:
+            from qiskit.circuit.library import Barrier as QiskitBarrier
+
             return QiskitBarrier(self.size)

mpqp/core/instruction/gates/custom_gate.py

@@ -1,16 +1,17 @@
-from typing import Optional
+from typing import TYPE_CHECKING, Optional
 
 from typeguard import typechecked
 
+if TYPE_CHECKING:
+    from qiskit.circuit import Parameter
+
 from mpqp.core.instruction.gates.gate import Gate
 from mpqp.core.instruction.gates.gate_definition import (
-    UnitaryMatrix,
     KrausRepresentation,
     PauliDecomposition,
+    UnitaryMatrix,
 )
 from mpqp.core.languages import Language
-from qiskit.circuit import Parameter
-from qiskit.quantum_info.operators import Operator as QiskitOperator
 
 
 @typechecked
@@ -36,8 +37,10 @@ def to_matrix(self):
     def to_other_language(
         self,
         language: Language = Language.QISKIT,
-        qiskit_parameters: Optional[set[Parameter]] = None,
+        qiskit_parameters: Optional[set["Parameter"]] = None,
     ):
+        from qiskit.quantum_info.operators import Operator as QiskitOperator
+
         if qiskit_parameters is None:
             qiskit_parameters = set()
         return QiskitOperator(self.matrix)
@@ -55,6 +58,7 @@ def decompose(self):
 @typechecked
 class KrausGate(CustomGate):
     """6M-TODO"""
+
     def __init__(
         self,
         definition: KrausRepresentation,
@@ -69,6 +73,7 @@ def __init__(
 @typechecked
 class PauliDecompositionGate(CustomGate):
     """6M-TODO"""
+
     def __init__(
         self,
         definition: PauliDecomposition,