Add docstrings for additional methods in #2480 (#2489)

Author: smitsanghavi

cirq/sim/clifford/clifford_simulator.py

@@ -254,9 +254,14 @@ def to_numpy(self):
         return self.ch_form.to_state_vector()
 
     def stabilizers(self) -> List[DensePauliString]:
+        """Returns the stabilizer generators of the state. These
+        are n operators {S_1,S_2,...,S_n} such that S_i |psi> = |psi> """
         return self.tableau.stabilizers()
 
     def destabilizers(self) -> List[DensePauliString]:
+        """Returns the destabilizer generators of the state. These
+        are n operators {S_1,S_2,...,S_n} such that along with the stabilizer
+        generators above generate the full Pauli group on n qubits."""
         return self.tableau.destabilizers()
 
     def wave_function(self):

cirq/sim/clifford/clifford_tableau.py

@@ -169,6 +169,15 @@ def g(x1, z1, x2, z2):
         self.zs[q1, :] ^= self.zs[q2, :]
 
     def _row_to_dense_pauli(self, i: int) -> DensePauliString:
+        """
+        Args:
+            i: index of the row in the tableau.
+        Returns:
+            A DensePauliString representing the row. The length of the string
+            is equal to the total number of qubits and each character
+            represents the effective single Pauli operator on that qubit. The
+            overall phase is captured in the coefficient.
+        """
         coefficient = -1 if self.rs[i] else 1
         pauli_mask = ""