Add additional basis gates rz, sx, x to basicaer. (Qiskit#6022)

* Add additional basis gates rz, sx, x to basicaer. This commit adds the Rz SX and X gates to basic aer simulators basis gate set. This is necessary for running simulations of the fake backends which are using the new basis set for the ibmq gates. This was extracted from Qiskit#5577 which is blocked on other work. * Fix lint and tests * Add missing error from docstring Co-authored-by: Thomas Alexander <[email protected]>
Cryoris · Mar 15, 2021 · edd76c7 · edd76c7
1 parent f3e2b7a
commit edd76c7
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Showing 5 changed files with 101 additions and 49 deletions.
diff --git a/qiskit/providers/basicaer/basicaertools.py b/qiskit/providers/basicaer/basicaertools.py
@@ -15,50 +15,56 @@
 """
 
 from string import ascii_uppercase, ascii_lowercase
+from typing import List, Optional
+
 import numpy as np
+
+import qiskit.circuit.library.standard_gates as gates
 from qiskit.exceptions import QiskitError
 
+# Single qubit gates supported by ``single_gate_params``.
+SINGLE_QUBIT_GATES = ('U', 'u1', 'u2', 'u3', 'rz', 'sx', 'x')
 
-def single_gate_params(gate, params=None):
-    """Apply a single qubit gate to the qubit.
+
+def single_gate_matrix(gate: str, params: Optional[List[float]] = None):
+    """Get the matrix for a single qubit.
 
     Args:
-        gate(str): the single qubit gate name
-        params(list): the operation parameters op['params']
+        gate: the single qubit gate name
+        params: the operation parameters op['params']
     Returns:
-        tuple: a tuple of U gate parameters (theta, phi, lam)
+        array: A numpy array representing the matrix
     Raises:
-        QiskitError: if the gate name is not valid
+        QiskitError: If a gate outside the supported set is passed in for the
+            ``Gate`` argument.
     """
-    if gate in ('U', 'u3'):
-        return params[0], params[1], params[2]
+    if params is None:
+        params = []
+
+    if gate == 'U':
+        gc = gates.UGate
+    elif gate == 'u3':
+        gc = gates.U3Gate
     elif gate == 'u2':
-        return np.pi / 2, params[0], params[1]
+        gc = gates.U2Gate
     elif gate == 'u1':
-        return 0, 0, params[0]
+        gc = gates.U1Gate
+    elif gate == 'rz':
+        gc = gates.RZGate
     elif gate == 'id':
-        return 0, 0, 0
-    raise QiskitError('Gate is not among the valid types: %s' % gate)
-
+        gc = gates.IGate
+    elif gate == 'sx':
+        gc = gates.SXGate
+    elif gate == 'x':
+        gc = gates.XGate
+    else:
+        raise QiskitError('Gate is not a valid basis gate for this simulator: %s' % gate)
 
-def single_gate_matrix(gate, params=None):
-    """Get the matrix for a single qubit.
-
-    Args:
-        gate(str): the single qubit gate name
-        params(list): the operation parameters op['params']
-    Returns:
-        array: A numpy array representing the matrix
-    """
+    return gc(*params).to_matrix()
 
-    # Converting sym to floats improves the performance of the simulator 10x.
-    # This a is a probable a FIXME since it might show bugs in the simulator.
-    (theta, phi, lam) = map(float, single_gate_params(gate, params))
 
-    return np.array([[np.cos(theta / 2),
-                      -np.exp(1j * lam) * np.sin(theta / 2)],
-                     [np.exp(1j * phi) * np.sin(theta / 2),
-                      np.exp(1j * phi + 1j * lam) * np.cos(theta / 2)]])
+# Cache CX matrix as no parameters.
+_CX_MATRIX = gates.CXGate().to_matrix()
 
 
 def cx_gate_matrix():

diff --git a/qiskit/providers/basicaer/qasm_simulator.py b/qiskit/providers/basicaer/qasm_simulator.py
@@ -43,6 +43,7 @@
 from qiskit.providers.basicaer.basicaerjob import BasicAerJob
 from .exceptions import BasicAerError
 from .basicaertools import single_gate_matrix
+from .basicaertools import SINGLE_QUBIT_GATES
 from .basicaertools import cx_gate_matrix
 from .basicaertools import einsum_vecmul_index
 
@@ -56,7 +57,7 @@ class QasmSimulatorPy(BaseBackend):
 
     DEFAULT_CONFIGURATION = {
         'backend_name': 'qasm_simulator',
-        'backend_version': '2.0.0',
+        'backend_version': '2.1.0',
         'n_qubits': min(24, MAX_QUBITS_MEMORY),
         'url': 'https://github.com/Qiskit/qiskit-terra',
         'simulator': True,
@@ -67,7 +68,7 @@ class QasmSimulatorPy(BaseBackend):
         'max_shots': 65536,
         'coupling_map': None,
         'description': 'A python simulator for qasm experiments',
-        'basis_gates': ['u1', 'u2', 'u3', 'cx', 'id', 'unitary'],
+        'basis_gates': ['u1', 'u2', 'u3', 'rz', 'sx', 'x', 'cx', 'id', 'unitary'],
         'gates': [
             {
                 'name': 'u1',
@@ -84,14 +85,29 @@ class QasmSimulatorPy(BaseBackend):
                 'parameters': ['theta', 'phi', 'lambda'],
                 'qasm_def': 'gate u3(theta,phi,lambda) q { U(theta,phi,lambda) q; }'
             },
+            {
+                'name': 'rz',
+                'parameters': ['phi'],
+                'qasm_def': 'gate rz(phi) q { U(0,0,phi) q; }'
+            },
+            {
+                'name': 'sx',
+                'parameters': [],
+                'qasm_def': 'gate sx(phi) q { U(pi/2,7*pi/2,pi/2) q; }'
+            },
+            {
+                'name': 'x',
+                'parameters': [],
+                'qasm_def': 'gate x q { U(pi,7*pi/2,pi/2) q; }'
+            },
             {
                 'name': 'cx',
-                'parameters': ['c', 't'],
+                'parameters': [],
                 'qasm_def': 'gate cx c,t { CX c,t; }'
             },
             {
                 'name': 'id',
-                'parameters': ['a'],
+                'parameters': [],
                 'qasm_def': 'gate id a { U(0,0,0) a; }'
             },
             {
@@ -512,7 +528,7 @@ def run_experiment(self, experiment):
                     qubits = operation.qubits
                     gate = operation.params[0]
                     self._add_unitary(gate, qubits)
-                elif operation.name in ('U', 'u1', 'u2', 'u3'):
+                elif operation.name in SINGLE_QUBIT_GATES:
                     params = getattr(operation, 'params', None)
                     qubit = operation.qubits[0]
                     gate = single_gate_matrix(operation.name, params)

diff --git a/qiskit/providers/basicaer/statevector_simulator.py b/qiskit/providers/basicaer/statevector_simulator.py
@@ -40,7 +40,7 @@ class StatevectorSimulatorPy(QasmSimulatorPy):
 
     DEFAULT_CONFIGURATION = {
         'backend_name': 'statevector_simulator',
-        'backend_version': '1.0.0',
+        'backend_version': '1.1.0',
         'n_qubits': min(24, MAX_QUBITS_MEMORY),
         'url': 'https://github.com/Qiskit/qiskit-terra',
         'simulator': True,
@@ -51,7 +51,7 @@ class StatevectorSimulatorPy(QasmSimulatorPy):
         'max_shots': 65536,
         'coupling_map': None,
         'description': 'A Python statevector simulator for qobj files',
-        'basis_gates': ['u1', 'u2', 'u3', 'cx', 'id', 'unitary'],
+        'basis_gates': ['u1', 'u2', 'u3', 'rz', 'sx', 'x', 'cx', 'id', 'unitary'],
         'gates': [
             {
                 'name': 'u1',
@@ -68,14 +68,29 @@ class StatevectorSimulatorPy(QasmSimulatorPy):
                 'parameters': ['theta', 'phi', 'lambda'],
                 'qasm_def': 'gate u3(theta,phi,lambda) q { U(theta,phi,lambda) q; }'
             },
+            {
+                'name': 'rz',
+                'parameters': ['phi'],
+                'qasm_def': 'gate rz(phi) q { U(0,0,phi) q; }'
+            },
+            {
+                'name': 'sx',
+                'parameters': [],
+                'qasm_def': 'gate sx(phi) q { U(pi/2,7*pi/2,pi/2) q; }'
+            },
+            {
+                'name': 'x',
+                'parameters': [],
+                'qasm_def': 'gate x q { U(pi,7*pi/2,pi/2) q; }'
+            },
             {
                 'name': 'cx',
-                'parameters': ['c', 't'],
+                'parameters': [],
                 'qasm_def': 'gate cx c,t { CX c,t; }'
             },
             {
                 'name': 'id',
-                'parameters': ['a'],
+                'parameters': [],
                 'qasm_def': 'gate id a { U(0,0,0) a; }'
             },
             {

diff --git a/qiskit/providers/basicaer/unitary_simulator.py b/qiskit/providers/basicaer/unitary_simulator.py
@@ -38,6 +38,7 @@
 from qiskit.result import Result
 from .exceptions import BasicAerError
 from .basicaertools import single_gate_matrix
+from .basicaertools import SINGLE_QUBIT_GATES
 from .basicaertools import cx_gate_matrix
 from .basicaertools import einsum_matmul_index
 
@@ -55,7 +56,7 @@ class UnitarySimulatorPy(BaseBackend):
 
     DEFAULT_CONFIGURATION = {
         'backend_name': 'unitary_simulator',
-        'backend_version': '1.0.0',
+        'backend_version': '1.1.0',
         'n_qubits': min(24, MAX_QUBITS_MEMORY),
         'url': 'https://github.com/Qiskit/qiskit-terra',
         'simulator': True,
@@ -66,7 +67,7 @@ class UnitarySimulatorPy(BaseBackend):
         'max_shots': 65536,
         'coupling_map': None,
         'description': 'A python simulator for unitary matrix corresponding to a circuit',
-        'basis_gates': ['u1', 'u2', 'u3', 'cx', 'id', 'unitary'],
+        'basis_gates': ['u1', 'u2', 'u3', 'rz', 'sx', 'x', 'cx', 'id', 'unitary'],
         'gates': [
             {
                 'name': 'u1',
@@ -83,14 +84,29 @@ class UnitarySimulatorPy(BaseBackend):
                 'parameters': ['theta', 'phi', 'lambda'],
                 'qasm_def': 'gate u3(theta,phi,lambda) q { U(theta,phi,lambda) q; }'
             },
+            {
+                'name': 'rz',
+                'parameters': ['phi'],
+                'qasm_def': 'gate rz(phi) q { U(0,0,phi) q; }'
+            },
+            {
+                'name': 'sx',
+                'parameters': [],
+                'qasm_def': 'gate sx(phi) q { U(pi/2,7*pi/2,pi/2) q; }'
+            },
+            {
+                'name': 'x',
+                'parameters': [],
+                'qasm_def': 'gate x q { U(pi,7*pi/2,pi/2) q; }'
+            },
             {
                 'name': 'cx',
-                'parameters': ['c', 't'],
+                'parameters': [],
                 'qasm_def': 'gate cx c,t { CX c,t; }'
             },
             {
                 'name': 'id',
-                'parameters': ['a'],
+                'parameters': [],
                 'qasm_def': 'gate id a { U(0,0,0) a; }'
             },
             {
@@ -317,7 +333,7 @@ def run_experiment(self, experiment):
                 gate = operation.params[0]
                 self._add_unitary(gate, qubits)
             # Check if single  gate
-            elif operation.name in ('U', 'u1', 'u2', 'u3'):
+            elif operation.name in SINGLE_QUBIT_GATES:
                 params = getattr(operation, 'params', None)
                 qubit = operation.qubits[0]
                 gate = single_gate_matrix(operation.name, params)

diff --git a/test/python/compiler/test_transpiler.py b/test/python/compiler/test_transpiler.py
@@ -32,7 +32,7 @@
 from qiskit.circuit import Parameter, Gate, Qubit, Clbit
 from qiskit.compiler import transpile
 from qiskit.converters import circuit_to_dag
-from qiskit.circuit.library import CXGate, U3Gate, U2Gate, U1Gate, RXGate, RYGate
+from qiskit.circuit.library import CXGate, U3Gate, U2Gate, U1Gate, RXGate, RYGate, RZGate
 from qiskit.test import QiskitTestCase, Path
 from qiskit.test.mock import FakeMelbourne, FakeRueschlikon, FakeAlmaden
 from qiskit.transpiler import Layout, CouplingMap
@@ -450,9 +450,8 @@ def test_parameterized_circuit_for_simulator(self):
 
         transpiled_qc = transpile(qc, backend=BasicAer.get_backend('qasm_simulator'))
 
-        expected_qc = QuantumCircuit(qr, global_phase=-1 * theta / 2.0)
-        expected_qc.append(U1Gate(theta), [qr[0]])
-
+        expected_qc = QuantumCircuit(qr)
+        expected_qc.append(RZGate(theta), [qr[0]])
         self.assertEqual(expected_qc, transpiled_qc)
 
     def test_parameterized_circuit_for_device(self):
@@ -484,8 +483,8 @@ def test_parameter_expression_circuit_for_simulator(self):
 
         transpiled_qc = transpile(qc, backend=BasicAer.get_backend('qasm_simulator'))
 
-        expected_qc = QuantumCircuit(qr, global_phase=-1 * square / 2.0)
-        expected_qc.append(U1Gate(square), [qr[0]])
+        expected_qc = QuantumCircuit(qr)
+        expected_qc.append(RZGate(square), [qr[0]])
         self.assertEqual(expected_qc, transpiled_qc)
 
     def test_parameter_expression_circuit_for_device(self):