Add docstring

src/qibotn/circuit_convertor.py

@@ -26,6 +26,11 @@ class QiboCircuitToEinsum:
         self.circuit = circuit
 
     def state_vector_operands(self):
+        """Create the operands for expectation computation in the interleave format.
+
+        Returns:
+            Operands for the contraction in the interleave format.
+        """
         input_bitstring = "0" * len(self.active_qubits)
 
         input_operands = self._get_bitstring_tensors(input_bitstring)
@@ -84,6 +89,17 @@ class QiboCircuitToEinsum:
         return (2, 2) * nqubits
 
     def init_intermediate_circuit(self, circuit):
+        """Initialize the intermediate circuit representation.
+
+        This method initializes the intermediate circuit representation by extracting gate matrices and qubit IDs
+        from the given quantum circuit.
+
+        Parameters:
+            circuit (object): The quantum circuit object.
+
+        Returns:
+            None
+        """
         self.gate_tensors = []
         gates_qubits = []
 
@@ -105,6 +121,18 @@ class QiboCircuitToEinsum:
         self.active_qubits = np.unique(gates_qubits)
 
     def init_basis_map(self, backend, dtype):
+        """Initialize the basis map for the quantum circuit.
+
+        This method initializes a basis map for the quantum circuit, which maps binary
+        strings representing qubit states to their corresponding quantum state vectors.
+
+        Parameters:
+            backend (object): The backend object providing the array conversion method.
+            dtype (object): The data type for the quantum state vectors.
+
+        Returns:
+            None
+        """
         asarray = backend.asarray
         state_0 = asarray([1, 0], dtype=dtype)
         state_1 = asarray([0, 1], dtype=dtype)
@@ -112,6 +140,17 @@ class QiboCircuitToEinsum:
         self.basis_map = {"0": state_0, "1": state_1}
 
     def init_inverse_circuit(self, circuit):
+        """Initialize the inverse circuit representation.
+
+        This method initializes the inverse circuit representation by extracting gate matrices and qubit IDs
+        from the given quantum circuit.
+
+        Parameters:
+            circuit (object): The quantum circuit object.
+
+        Returns:
+            None
+        """
         self.gate_tensors_inverse = []
         gates_qubits_inverse = []
 
@@ -159,6 +198,14 @@ class QiboCircuitToEinsum:
         return gates
 
     def expectation_operands(self, pauli_string):
+        """Create the operands for pauli string expectation computation in the interleave format.
+
+        Args:
+            pauli_string: A string representating the list of pauli gates.
+
+        Returns:
+            Operands for the contraction in the interleave format.
+        """
         input_bitstring = "0" * self.circuit.nqubits
 
         input_operands = self._get_bitstring_tensors(input_bitstring)