chores: imports improvements and inplace simplify

Author: Henri-ColibrITD

mpqp/all.py

@@ -53,10 +53,12 @@
     ComputationalBasis,
     ExpectationMeasure,
     HadamardBasis,
-    Measure,
-    Observable,
-    VariableSizeBasis,
 )
+from .measures import I as Iop
+from .measures import Measure, Observable, VariableSizeBasis
+from .measures import X as Xop
+from .measures import Y as Yop
+from .measures import Z as Zop
 from .qasm import open_qasm_file_conversion_2_to_3, open_qasm_hard_includes
 
 theta, k = symbols("θ k")  # type: ignore

mpqp/core/instruction/measurement/__init__.py

@@ -1,5 +1,6 @@
 # pyright: reportUnusedImport=false
-from .basis import ComputationalBasis, Basis, HadamardBasis, VariableSizeBasis
+from .basis import Basis, ComputationalBasis, HadamardBasis, VariableSizeBasis
 from .basis_measure import BasisMeasure
 from .expectation_value import ExpectationMeasure, Observable
 from .measure import Measure
+from .pauli_string import I, X, Y, Z

mpqp/core/instruction/measurement/pauli_string.py

@@ -138,8 +138,12 @@ def __eq__(self, other: object) -> bool:
             return False
         return self.to_dict() == other.to_dict()
 
-    def simplify(self) -> PauliString:
-        """Simplify the PauliString by combining like terms and removing terms with zero coefficients.
+    def simplify(self, inplace: bool = False) -> PauliString:
+        """Simplify the PauliString by combining like terms and removing terms
+        with zero coefficients.
+
+        Args:
+            inplace: If the simplify should change self.
 
         Example:
             >>> ps = I @ I - 2 * I @ I + Z @ I - Z @ I
@@ -166,6 +170,8 @@ def simplify(self) -> PauliString:
             res.monomials.append(
                 PauliStringMonomial(0, [I for _ in range(self.nb_qubits)])
             )
+        if inplace:
+            self._monomials = res.monomials
         return res
 
     def to_matrix(self) -> Matrix:
@@ -357,7 +363,7 @@ def __matmul__(self, other: PauliString):
         res @= other
         return res
 
-    def simplify(self):
+    def simplify(self, inplace: bool = False):
         return deepcopy(self)
 
     def __eq__(self, other: object) -> bool: