fix: fixing types and special cases for diagonal observables

Author: hJaffaliColibritd

mpqp/core/instruction/measurement/expectation_value.py

@@ -112,17 +112,21 @@ def __init__(self, observable: Matrix | list[Real] | PauliString):
 
                     self._matrix = np.array(observable)
 
+                else:
+                    self._is_diagonal = True
+                    self._diag_elements = observable.real
+
             # correspond to isinstance(observable, list)
             else:
                 self._is_diagonal = True
-                self._diag_elements = observable
+                self._diag_elements = np.array(observable)
 
     @property
     def matrix(self) -> Matrix:
         """The matrix representation of the observable."""
         if self._matrix is None:
             if self.is_diagonal:
-                self._matrix = np.diag(self._diag_elements)
+                self._matrix = np.diag(self.diagonal_elements)
             else:
                 self._matrix = self.pauli_string.to_matrix()
         matrix = copy.deepcopy(self._matrix).astype(np.complex64)
@@ -134,7 +138,7 @@ def pauli_string(self) -> PauliString:
         if self._pauli_string is None:
             if self.is_diagonal:
                 self._pauli_string = PauliString.from_diagonal_elements(
-                    self._diag_elements
+                    self.diagonal_elements
                 )
             else:
                 self._pauli_string = PauliString.from_matrix(self.matrix)
@@ -146,7 +150,7 @@ def diagonal_elements(self) -> npt.NDArray[np.float32]:
         """The diagonal elements of the matrix representing the observable (diagonal or not)."""
         if self._diag_elements is None:
             self._diag_elements = np.diagonal(self.matrix)
-        return self._diag_elements
+        return copy.deepcopy(self._diag_elements).real
 
     @matrix.setter
     def matrix(self, matrix: Matrix):

mpqp/tools/obs_decomposition.py

@@ -307,7 +307,7 @@ def get_monomial(self) -> PauliStringMonomial:
 def compute_coefficients_diagonal_case(
     m: list[bool],
     current_node: DiagPauliNode,
-    diag_elements: npt.NDArray[np.float64],
+    diag_elements: npt.NDArray[np.float32],
     monomial_list: list[PauliStringMonomial],
 ):
     """Computes coefficients for the current node in the pauli tree based on the
@@ -356,7 +356,7 @@ def update_tree_diagonal_case(current_node: DiagPauliNode, m: list[bool]):
 def generate_and_explore_node_diagonal_case(
     m: list[bool],
     current_node: DiagPauliNode,
-    diag_elements: npt.NDArray[np.float64],
+    diag_elements: npt.NDArray[np.float32],
     n: int,
     monomials: list[PauliStringMonomial],
     progression: Optional[list[int]] = None,
@@ -404,7 +404,7 @@ def generate_and_explore_node_diagonal_case(
 
 @typechecked
 def decompose_diagonal_observable_ptdr(
-    diag_elements: list[Real] | npt.NDArray[np.float64], print_progression: bool = False
+    diag_elements: list[Real] | npt.NDArray[np.float32], print_progression: bool = False
 ) -> PauliString:
     """Decomposes a diagonal observable into a Pauli string representation.
 
@@ -480,7 +480,7 @@ def generate_hadamard(n: int) -> npt.NDArray[np.int8]:
 
 
 def compute_coefficients_walsh(
-    H_matrix: npt.NDArray[np.int8], diagonal_elements: npt.NDArray[np.float64]
+    H_matrix: npt.NDArray[np.int8], diagonal_elements: npt.NDArray[np.float32]
 ) -> list[float]:
     """Computes the coefficients using the Walsh-Hadamard transform.
 
@@ -505,7 +505,7 @@ def compute_coefficients_walsh(
 
 @typechecked
 def decompose_diagonal_observable_walsh_hadamard(
-    diag_elements: list[Real] | npt.NDArray[np.float64],
+    diag_elements: list[Real] | npt.NDArray[np.float32],
 ) -> PauliString:
     """Decomposes the observable represented by the diagonal elements into a
     Pauli string using the Walsh-Hadamard transform.
@@ -535,7 +535,7 @@ def decompose_diagonal_observable_walsh_hadamard(
         if TYPE_CHECKING:
             assert isinstance(m, PauliStringMonomial)
         if c != 0.0:
-            m.coef = c
+            m.coef = c.real
             final_monomials.append(m)
 
     return PauliString(final_monomials)