Data structures for specifying input states

docs/source/changes.rst

@@ -4,6 +4,14 @@ Changelog
 v2.4 (Development)
 ------------------
 
+- Operator estimation data structures introduced in v2.2 have changed. ExperimentSetting's had
+  two members: in_operator and out_operator. out_operator is unchanged. in_operator has been
+  renamed to in_state and its data type is now ``TensorProductState`` instead of ``PauliTerm``.
+  It was always an abuse of notation to interpret pauli operators as defining initial states.
+  Analogous to the Pauli helper functions sI, sX, sY, and sZ, TensorProductStates are constructed
+  by multiplying together terms generated by the helper functions plusX, minusX, plusY, minusY,
+  plusZ, minusZ, and vacuum. This functionality enables process tomography and process DFE (gh-770).
+
 
 v2.3 (January 28, 2019)
 -----------------------

pyquil/gate_matrices.py

@@ -287,6 +287,33 @@ def bitphase_flip_operators(p):
     'bitphase_flip': bitphase_flip_operators,
 }
 
+SIC0 = np.array([1, 0])
+SIC1 = np.array([1, np.sqrt(2)]) / np.sqrt(3)
+SIC2 = np.array([1, np.exp(-np.pi * 2j / 3) * np.sqrt(2)]) / np.sqrt(3)
+SIC3 = np.array([1, np.exp(np.pi * 2j / 3) * np.sqrt(2)]) / np.sqrt(3)
+
+STATES = {
+    'X': [
+        np.array([1, 1]) / np.sqrt(2),
+        np.array([1, -1]) / np.sqrt(2),
+    ],
+    'Y': [
+        np.array([1, 1j]) / np.sqrt(2),
+        np.array([1, -1j]) / np.sqrt(2),
+    ],
+    'Z': [
+        np.array([1, 0]),
+        np.array([0, 1]),
+    ],
+    'SIC': [
+        SIC0,
+        SIC1,
+        SIC2,
+        SIC3,
+    ]
+}
+
 __all__ = list(QUANTUM_GATES.keys()) + ['relaxation_operators', 'dephasing_operators',
                                         'depolarizing_operators', 'phase_flip_operators',
-                                        'bit_flip_operators', 'bitphase_flip_operators']
+                                        'bit_flip_operators', 'bitphase_flip_operators',
+                                        'SIC_BASIS', 'SIC0', 'SIC1', 'SIC2', 'SIC3']