Add support for StatePrep

CHANGELOG.md

@@ -1,11 +1,14 @@
-# Release 0.30.0-dev
+# Release 0.32.0-dev
 
 ### New features since last release
 
 ### Breaking changes
 
 ### Improvements
 
+* Added support for `qml.StatePrep` as a state preparation operation. 
+  [(#54)](https://github.com/PennyLaneAI/pennylane-qulacs/pull/54)
+
 ### Documentation
 
 ### Bug fixes
@@ -14,6 +17,8 @@
 
 This release contains contributions from (in alphabetical order):
 
+Jay Soni
+
 ---
 # Release 0.29.0
 

pennylane_qulacs/qulacs_device.py

@@ -21,7 +21,15 @@
 import numpy as np
 
 from pennylane import QubitDevice, DeviceError
-from pennylane.ops import QubitStateVector, BasisState, QubitUnitary, CRZ, PhaseShift, Adjoint
+from pennylane.ops import (
+    QubitStateVector,
+    BasisState,
+    QubitUnitary,
+    CRZ,
+    PhaseShift,
+    Adjoint,
+    StatePrep,
+)
 
 import qulacs.gate as gate
 from qulacs import QuantumCircuit, QuantumState, Observable
@@ -85,6 +93,7 @@ class QulacsDevice(QubitDevice):
     }
 
     _operation_map = {
+        "StatePrep": None,
         "QubitStateVector": None,
         "BasisState": None,
         "QubitUnitary": None,
@@ -159,7 +168,7 @@ def apply_operations(self, operations):
         """
 
         for i, op in enumerate(operations):
-            if i > 0 and isinstance(op, (QubitStateVector, BasisState)):
+            if i > 0 and isinstance(op, (QubitStateVector, BasisState, StatePrep)):
                 raise DeviceError(
                     "Operation {} cannot be used after other Operations have already been applied "
                     "on a {} device.".format(op.name, self.short_name)
@@ -169,7 +178,7 @@ def apply_operations(self, operations):
                 inverse = True
                 op = op.base
 
-            if isinstance(op, QubitStateVector):
+            if isinstance(op, (QubitStateVector, StatePrep)):
                 self._apply_qubit_state_vector(op)
             elif isinstance(op, BasisState):
                 self._apply_basis_state(op)

requirements.txt

@@ -1,3 +1,3 @@
-pennylane>=0.15
+git+https://github.com/PennyLaneAI/pennylane.git
 Qulacs>=0.1.10.1
 numpy~=1.16

tests/test_apply.py

@@ -163,27 +163,29 @@ def test_basis_state_on_wires_subset(self, state, device_wires, op_wires, tol):
         expected = dev._expand_state(expected, op_wires)
         assert np.allclose(res, expected, tol)
 
-    def test_qubit_state_vector(self, init_state, tol):
-        """Test QubitStateVector application"""
+    @pytest.mark.parametrize("state_prep_op", (qml.QubitStateVector, qml.StatePrep))
+    def test_qubit_state_vector(self, init_state, state_prep_op, tol):
+        """Test QubitStateVector and StatePrep application"""
         dev = QulacsDevice(1)
         state = init_state(1)
 
-        op = qml.QubitStateVector(state, wires=[0])
+        op = state_prep_op(state, wires=[0])
         dev.apply([op])
         dev._obs_queue = []
 
         res = dev.state
         expected = state
         assert np.allclose(res, expected, tol)
 
+    @pytest.mark.parametrize("state_prep_op", (qml.QubitStateVector, qml.StatePrep))
     @pytest.mark.parametrize("device_wires", [3, 4, 5])
     @pytest.mark.parametrize("op_wires", [[0], [2], [0, 1], [1, 0], [2, 0]])
-    def test_qubit_state_vector_on_wires_subset(self, init_state, device_wires, op_wires, tol):
-        """Test QubitStateVector application on a subset of device wires"""
+    def test_qubit_state_vector_on_wires_subset(self, init_state, device_wires, op_wires, state_prep_op, tol):
+        """Test QubitStateVector and StatePrep application on a subset of device wires"""
         dev = QulacsDevice(device_wires)
         state = init_state(len(op_wires))
 
-        op = qml.QubitStateVector(state, wires=op_wires)
+        op = state_prep_op(state, wires=op_wires)
         dev.apply([op])
         dev._obs_queue = []
 
@@ -198,7 +200,7 @@ def test_single_qubit_no_parameters(self, init_state, op, mat, tol):
         dev = QulacsDevice(1)
         state = init_state(1)
 
-        dev.apply([qml.QubitStateVector(state, wires=[0]), op])
+        dev.apply([qml.StatePrep(state, wires=[0]), op])
         dev._obs_queue = []
 
         res = dev.state
@@ -213,7 +215,7 @@ def test_single_qubit_parameters(self, init_state, op, func, theta, tol):
         state = init_state(1)
 
         op.data = [theta]
-        dev.apply([qml.QubitStateVector(state, wires=[0]), op])
+        dev.apply([qml.StatePrep(state, wires=[0]), op])
         dev._obs_queue = []
 
         res = dev.state
@@ -226,7 +228,7 @@ def test_two_qubit_no_parameters(self, init_state, op, mat, tol):
         dev = QulacsDevice(2)
         state = init_state(2)
 
-        dev.apply([qml.QubitStateVector(state, wires=[0, 1]), op])
+        dev.apply([qml.StatePrep(state, wires=[0, 1]), op])
         dev._obs_queue = []
 
         res = dev.state
@@ -242,7 +244,7 @@ def test_qubit_unitary(self, init_state, mat, tol):
         state = init_state(N)
 
         op = qml.QubitUnitary(mat, wires=list(range(N)))
-        dev.apply([qml.QubitStateVector(state, wires=list(range(N))), op])
+        dev.apply([qml.StatePrep(state, wires=list(range(N))), op])
         dev._obs_queue = []
 
         res = dev.state
@@ -262,7 +264,7 @@ def test_three_qubit_no_parameters(self, init_state, op, mat, tol):
         dev = QulacsDevice(3)
         state = init_state(3)
 
-        dev.apply([qml.QubitStateVector(state, wires=[0, 1, 2]), op])
+        dev.apply([qml.StatePrep(state, wires=[0, 1, 2]), op])
         dev._obs_queue = []
 
         res = dev.state
@@ -277,7 +279,7 @@ def test_two_qubit_parameters(self, init_state, op, func, theta, tol):
         state = init_state(2)
 
         op.data = [theta]
-        dev.apply([qml.QubitStateVector(state, wires=[0, 1]), op])
+        dev.apply([qml.StatePrep(state, wires=[0, 1]), op])
 
         dev._obs_queue = []