qft, iqft and tests

qlasskit/qcircuit/exporter_cirq.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import math
 from typing import Literal
 
 from . import gates
@@ -54,6 +55,13 @@ def _decompose_(self, qubits):
                             )
                             yield gg(list(map(lambda wx: qubits[w], w)))
 
+                        elif isinstance(g, gates.Swap):
+                            yield cirq.SWAP(qubits[w[0]], qubits[w[1]])
+
+                        elif isinstance(g, gates.CP):
+                            cphase_gate = cirq.CZPowGate(exponent=p / math.pi)
+                            yield cphase_gate(qubits[w[0]], qubits[w[1]])
+
                         elif hasattr(cirq, g_name):
                             yield getattr(cirq, g_name)(
                                 *list(map(lambda x: qubits[x], w))

qlasskit/qcircuit/exporter_pennylane.py

@@ -52,6 +52,12 @@ def export(self, _selfqc, mode: Literal["circuit", "gate"]):  # noqa: C901
             elif isinstance(g, gates.MCtrl) and isinstance(g.gate, gates.Z):
                 ops.append(qml.CZ(wires=w))
 
+            elif isinstance(g, gates.Swap):
+                ops.append(qml.SWAP(wires=w))
+
+            elif isinstance(g, gates.CP):
+                ops.append(qml.CPhase(p, wires=w))
+
             elif isinstance(g, gates.Barrier):
                 pass
 
@@ -62,6 +68,6 @@ def export(self, _selfqc, mode: Literal["circuit", "gate"]):  # noqa: C901
                 ops.append(getattr(qml, g_name)(wires=w))
 
             else:
-                raise Exception(f"not handled {g}")
+                raise Exception(f"Gate not handled for pennylane exporter: {g_name}")
 
         return qml.tape.QuantumTape(ops)

qlasskit/qcircuit/exporter_qasm.py

@@ -28,7 +28,10 @@ def export(self, _selfqc, mode: Literal["circuit", "gate"]):
                 continue
 
             qbs = list(map(lambda gq: _selfqc.get_key_by_index(gq), ws))
-            gate_qasm += f'\t{g.__name__.lower()} {" ".join(qbs)}\n'
+            if p:
+                gate_qasm += f'\t{g.__name__.lower()}({p:.2f}) {" ".join(qbs)}\n'
+            else:
+                gate_qasm += f'\t{g.__name__.lower()} {" ".join(qbs)}\n'
         gate_qasm += "}\n\n"
 
         if mode == "gate":

qlasskit/qcircuit/exporter_qiskit.py

@@ -43,10 +43,13 @@ def export(self, _selfqc, mode: Literal["circuit", "gate"]):  # noqa: C901
                 pass
 
             elif hasattr(qc, g_name):
-                getattr(qc, g_name)(*w)
+                if p:
+                    getattr(qc, g_name)(p, *w)
+                else:
+                    getattr(qc, g_name)(*w)
 
             else:
-                raise Exception(f"not handled {g}")
+                raise Exception(f"Gate not handled for qiskit exporter: {g_name}")
 
         if mode == "gate":
             qc.remove_final_measurements()

qlasskit/qcircuit/exporter_sympy.py

@@ -14,12 +14,15 @@
 
 from typing import Literal
 
-from sympy.physics.quantum.gate import CNOT, CGate, H, X, XGate
+from sympy.physics.quantum.gate import CNOT, SWAP, CGate, H, X, XGate
 from sympy.physics.quantum.qubit import Qubit
 
 from . import gates
 from .exporter import QCircuitExporter
 
+# def cp(theta, q0, q1):
+#     return CGate((q0,), Z(q1)**(theta))
+
 
 def mcx(w):
     return CGate(tuple(w[0:-1]), XGate(w[-1]))
@@ -30,29 +33,34 @@ def toffoli(q0, q1, q2):
 
 
 class SympyExporter(QCircuitExporter):
-    def export(self, _selfqc, mode: Literal["circuit", "gate"]):
-        qstate = Qubit("0" * _selfqc.num_qubits) if mode == 'circuit' else None
+    def export(self, _selfqc, mode: Literal["circuit", "gate"]):  # noqa: C901
+        qstate = Qubit("0" * _selfqc.num_qubits) if mode == "circuit" else None
 
         for g, w, p in _selfqc.gates:
+            g_name = g.__class__.__name__
             ga = None
             if isinstance(g, gates.X):
                 ga = X(w[0])
             elif isinstance(g, gates.H):
                 ga = H(w[0])
             elif isinstance(g, gates.CX):
                 ga = CNOT(w[0], w[1])
+            # elif isinstance(g, gates.CP):
+            #     ga = cp(p, w[0], w[1])
+            elif isinstance(g, gates.Swap):
+                ga = SWAP(w[0], w[1])
             elif isinstance(g, gates.CCX) or isinstance(g, gates.MCX):
                 ga = mcx(w)
             elif isinstance(g, gates.Barrier) and mode != "gate":
                 pass
             elif isinstance(g, gates.NopGate):
                 pass
             else:
-                raise Exception("not handled")
+                raise Exception(f"Gate not handled for sympy exporter: {g_name}")
 
             if ga and qstate:
                 qstate = ga * qstate
             elif ga:
                 qstate = ga
-                
+
         return qstate

qlasskit/qcircuit/gates.py

@@ -72,11 +72,26 @@ def __init__(self):
         super().__init__("Z")
 
 
+class P(QGate):
+    def __init__(self):
+        super().__init__("P")
+
+
+class Swap(QGate):
+    def __init__(self):
+        super().__init__("SWAP", 2)
+
+
 class CX(QControlledGate):
     def __init__(self):
         super().__init__(X(), 1)
 
 
+class CP(QControlledGate):
+    def __init__(self):
+        super().__init__(P(), 1)
+
+
 class CCX(QControlledGate):
     def __init__(self):
         super().__init__(X(), 2)

qlasskit/qcircuit/qcircuit.py

@@ -6,13 +6,14 @@
 
 # http://www.apache.org/licenses/LICENSE-2.0
 
-import copy
-
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+import copy
+import math
 from typing import Any, List, Literal, Tuple, Union
 
 from sympy import Symbol
@@ -227,6 +228,52 @@ def mcx(self, wl: List[int], target):
         wl = list(map(lambda w: self[w], wl))
         self.append(gates.MCX(len(wl)), wl + [target])
 
+    def swap(self, w1, w2):
+        w1, w2 = self[w1], self[w2]
+        self.append(gates.Swap(), [w1, w2])
+
+    def cp(self, phase, w1, w2):
+        """CP gate"""
+        w1, w2 = self[w1], self[w2]
+        self.append(gates.CP(), [w1, w2], phase)
+
+    def qft(self, wl: List[int]):
+        """Apply the quantum fourier transform"""
+        n = len(wl)
+        wl = list(map(lambda w: self[w], wl))
+
+        for i in range(n):
+            # Apply the Hadamard gate on the qubit at index i
+            self.h(wl[i])
+
+            # Apply the controlled phase rotation gates
+            for j in range(i + 1, n):
+                phase = 2 * math.pi / (2 ** (j - i + 1))
+                self.cp(phase, wl[j], wl[i])
+
+        # Swap the qubits to get them in the correct order
+        for i in range(n // 2):
+            self.swap(wl[i], wl[n - i - 1])
+
+    def iqft(self, wl: List[int]):
+        """Apply the inverse quantum fourier transform"""
+        n = len(wl)
+        wl = list(map(lambda w: self[w], wl))
+
+        # Swap the qubits to get them in the reverse order for IQFT
+        for i in range(n // 2):
+            self.swap(wl[i], wl[n - i - 1])
+
+        # Apply the IQFT
+        for i in reversed(range(n)):
+            # Apply the controlled phase rotation gates in reverse order
+            for j in reversed(range(i + 1, n)):
+                angle = -2 * math.pi / (2 ** (j - i + 1))
+                self.cp(angle, wl[j], wl[i])
+
+            # Apply the Hadamard gate on the qubit at index i
+            self.h(wl[i])
+
     def export(
         self,
         mode: Literal["circuit", "gate"] = "circuit",

test/test_qcircuit.py

@@ -12,12 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import ast
 import unittest
 
 from sympy import Symbol
-from sympy.physics.quantum.qapply import qapply
-from sympy.physics.quantum.qubit import Qubit, measure_all
 
 from qlasskit.qcircuit import QCircuit, QCircuitEnhanced, gates
 
@@ -32,8 +29,13 @@ def test_base(self):
 
     def test_base_mapping(self):
         qc = QCircuit()
-        a, b, c = qc.add_qubit("a"), qc.add_qubit("b"), qc.add_qubit(Symbol("c"))
+        a, b, c = (
+            qc.add_qubit("a"),
+            qc.add_qubit("b"),
+            qc.add_qubit(Symbol("c")),
+        )
         qc.ccx("a", Symbol("b"), c)
+        qc.ccx(a, b, c)
         self.assertEqual(qc.num_qubits, 3)
         self.assertTrue(isinstance(qc.gates[0][0], gates.CCX))
         self.assertEqual(qc.gates[0][1:], ([0, 1, 2], None))
@@ -60,7 +62,7 @@ def test_augassign_othercirc(self):
 
     def test_get_key_by_index(self):
         qc = QCircuit()
-        a, b = qc.add_qubit("a"), qc.add_qubit("b")
+        a, b = qc.add_qubit("a"), qc.add_qubit("b")  # noqa: F841
         self.assertRaises(Exception, lambda qc: qc.get_key_by_index(3), qc)
         self.assertEqual(qc.get_key_by_index(0), "a")
 
@@ -126,3 +128,26 @@ def test_uncompute_all(self):
         qc.uncompute(a)
         qc.uncompute_all([r])
         # qc.draw()
+
+
+class TestQCircuitQFT(unittest.TestCase):
+    def test_qft(self):
+        qc = QCircuit(3)
+        qc.qft([0, 1, 2])
+        self.assertEqual(qc.num_gates, 7)
+
+        qc.iqft([0, 1, 2])
+        self.assertEqual(qc.num_gates, 14)
+
+        for i in range(int(qc.num_gates / 2)):
+            a = qc.gates[i]
+            b = qc.gates[qc.num_gates - i - 1]
+
+            self.assertEqual(a[0].__name__, b[0].__name__)
+            self.assertEqual(a[1], b[1])
+
+            if a[2]:
+                self.assertEqual(a[2], -b[2])
+
+        counts = qiskit_measure_and_count(qc.export("circuit", "qiskit"), shots=1024)
+        self.assertEqual(counts, {"000": 1024})

test/test_qcircuit_exporters.py

@@ -11,19 +11,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
-import ast
 import unittest
 
 import cirq
 import numpy as np
 import pennylane as qml
 from parameterized import parameterized_class
-from sympy import Symbol
 from sympy.physics.quantum.qapply import qapply
 from sympy.physics.quantum.qubit import Qubit, measure_all
 
-from qlasskit.qcircuit import QCircuit, QCircuitEnhanced, gates
+from qlasskit.qcircuit import QCircuit
 
 from .utils import qiskit_measure_and_count
 
@@ -53,12 +50,28 @@ def bell_circuit():
     return qc
 
 
+def qft_circuit():
+    qc = QCircuit()
+    a, b, c = qc.add_qubit("a"), qc.add_qubit("b"), qc.add_qubit("c")
+    qc.qft([a, b, c])
+    qc.iqft([a, b, c])
+    return qc
+
+
 @parameterized_class(
     ("qc", "result"),
     [
         (cx_circuit(), "gate qc q0 q1 {\n\tx q0\n\tcx q0 q1\n}\n\n"),
         (ccx_circuit(), "gate qc a b c {\n\tx a\n\tx b\n\tccx a b c\n}\n\n"),
         (bell_circuit(), "gate qc a b {\n\th a\n\tcx a b\n}\n\n"),
+        (
+            qft_circuit(),
+            (
+                "gate qc a b c {\n\th a\n\tcp(1.57) b a\n\tcp(0.79) c a\n\th b\n"
+                "\tcp(1.57) c b\n\th c\n\tswap a c\n\tswap a c\n\th c\n"
+                "\tcp(-1.57) c b\n\th b\n\tcp(-0.79) c a\n\tcp(-1.57) b a\n\th a\n}\n\n"
+            ),
+        ),
     ],
 )
 class TestQCircuitExportQASM(unittest.TestCase):
@@ -77,6 +90,7 @@ def test_export_qasm_circuit(self):
         (cx_circuit(), [(Qubit("11"), 1)]),
         (ccx_circuit(), [(Qubit("111"), 1)]),
         (bell_circuit(), [(Qubit("00"), 1 / 2), (Qubit("11"), 1 / 2)]),
+        # (qft_circuit(), [(Qubit("000"), 1)]),
     ],
 )
 class TestQCircuitExportSympy(unittest.TestCase):
@@ -98,6 +112,7 @@ def test_export_sympy_gate(self):
     [
         (cx_circuit(), {"11": 1}),
         (ccx_circuit(), {"111": 1}),
+        (qft_circuit(), {"000": 1}),
     ],
 )
 class TestQCircuitExportQiskit(unittest.TestCase):
@@ -125,6 +140,14 @@ def test_export_qiskit(self):
                 "q(2)": np.array([[[1]]], dtype=np.int8),
             },
         ),
+        (
+            qft_circuit(),
+            {
+                "q(0)": np.array([[[0]]], dtype=np.int8),
+                "q(1)": np.array([[[0]]], dtype=np.int8),
+                "q(2)": np.array([[[0]]], dtype=np.int8),
+            },
+        ),
     ],
 )
 class TestQCircuitExportCirq(unittest.TestCase):
@@ -161,6 +184,7 @@ def test_export_cirq_gate(self):
         (cx_circuit(), [0, 0, 0, 1]),
         (ccx_circuit(), [0, 0, 0, 0, 0, 0, 0, 1]),
         (bell_circuit(), [0.5, 0, 0, 0.5]),
+        (qft_circuit(), [1, 0, 0, 0, 0, 0, 0, 0]),
     ],
 )
 class TestQCircuitExportPennylane(unittest.TestCase):