New algorithm for RB building Cliffords by layers (#892)

* New algorithm for generating Clifford circuits for single qubit. We generate once all 24 transpiled Cliffords. Then, for every rb_circuit, select Cliffords at random and compose them to a circuit * Changed basis for transpilation to match the one in single_qubit_test. Added parameter to all calls to compose to use inplace=True. Removed redundant method generate_all_transpiled_clifford_circuits * Modified the methods in create_clifford_map so that compose does not use front=True, because I assume front=False when creating the circuits * Changed generation of generation of random numbers to be identical to the previous version of rb_experiment. * Test to run on device * added methods for new algorithm to generate rb circuits: build_rb_circuits, generate_1q_transpiled_clifford_circuits * Added the method _layout_for_rb_single_qubit and added test_full_sampling_single_qubit * In test_full_sampling_single_qubit fixed num_samples to be 1, because otherwise randomization is not identical in the two experiments * Tidied up build_rb_circuits * Added documentation and moved methods * Added test_single_qubit_parallel * Changed name _format_data to format_data because the method wasn't being called by the child class CurveAnalaysis. Added parameter to rb_experiment to determine whether to use the old algorithm or new one * Fixed handling of num_samples>1. Cleaned out prints. Reverted previous change regarding _format_data * Added assertExperimentDone to test_single-qubit_parallel. Fixed parameters for test_full_sampling_single_qubit * Modified assertAllIdentity to support circuits with rz gates * Changed name _new_rb to _transpiled_rb. Also changed default to be False, so that all tests will pass * removed fast_rb.py * removed rb_on_device.py * Removed temporary 'import time' * Added support for interleaved rb single qubit * Fixed handling of interleaved element * Fixed bug caused by change of interface of _buil_rb_circuits after adding support for interleave * added test_number_to_clifford_mapping and fixed the method num_from_1_qubit_clifford * Added support for computation of the Clifford to number mapping of a circuit * Moved setting of interleaved metadata to be under 'if is_interleaved' * Added transpilation of interleaved element before creating the rb circuits. Transformed interleaved element into a transpiled clifford circuit. Added relevant tests * Fixed incorrect parameter 'qubits' in test_non_clifford_interleaved_element * Added support for 'delay' as interleaved element * Moved setting of basis gates to circuits(), because in __init__ the transpile_options are not available yet * Cleaned up setting of tranpile_options in the test. Added call to generate_1q_transpiled_clifford_circuits in InterleavedRB.circuits() * Changed the clifford compose mapping so that the rhs includes only single-gate cliffords. The purpose is to reduce the size of the mapping table * Changed all methods in CliffordUtils to be classmethod * Fixes following changes in CliffordUtils * Changed structure of CLIFF_COMPOSE_DATA to be an array instead of a dict, for performance reasons. The index in the array is computed in compose_num_with_clifford * Improved _layout_for_rb_single_qubit to be more robust * Documentation, black, pylint * black * Removed the parameter transpiled_rb used for choosing whether to use old algorithm or new one. * Cleaning up * Generated transpiled clifford circuits for 2 qubits, and stored in a file. Adding load from this file in circuits() * re-generated transpiled circuits * Added support for compose_num_with_clifford_2q. Added suitable test - test_number_to_clifford_mapping_2q. * Created method load_transpiled_cliff_circuits * Added support for two sets of basis gates and their corresponding transpiled clifford files * United the two class variables _transpiled_cliff_circuits_1q and _transpiled_cliff_circuits_2q to a single dict * Added setting of transpile_options to all tests * Fixed error messages * United methods compose_num_with_clifford and num_from_clifford_single_gate for 1 and 2 qubits. Interface changes in StandardRB towards uniting functionality for 1 and 2 qubits * Unified the format for CLIFF_SINGLE_GATE_MAP_1Q and CLIFF_SINGLE_GATE_MAP_2Q * Added method clifford_inverse_by_num to unite handling of 1 and 2 qubit-rb * Fixes to support 1 and 2 qubits in _build_rb_circuits * Fixed more places where the code assumed 1 qubit rb * Fix for handling of delay. Changed test_interleaving_circuit_with_delay to suit transpiled circuits * changed basis gates in test, because rz is not supported in conversion to Clifford * Extended lenths for test, because test was failing for statistical reasons * changed name of method after addition of 2q * black and lint * black, lint and documentation * black, lint, cleaning * Removed legacy code. Additional cleaning * Removed more legacy code. More cleaning * Removed pylint messages for the data file * pylint, and use method CliffordUtils.file_name * Removed additional legacy code * Release notes * Added missing () * Fixed error message * Added QiskitError to documentation * black * Fixed error message * Changed varible name * attempt to fix documentation failure in CI * pylint * Added transpile options to every experiment * Made setting transpile_options mandatory, because if basis_gates are taken from backend, then the names of the transpiled clifford files don't match * Split test_rb_utils into itself and test_clifford_utils * Added tests for composing a clifford with a number * Added test for inverse clifford by num * Changed random to rng because of failure on Windows * Removed dependency on Aer for transpile. Removed the method transpile_single_clifford and use transpile() directly instead * Changed parameter backend to be optional, as it was before * Improved format for CLIFF_SINGLE_GATE_MAP, CLIFF_COMPOSE_DATA, CLIFF_INVERSE_DATA * Changed usage from cliff.__repr__ to repr(cliff) * Fixed a bug where transpiled_circuits were loaded multiple times * New algorithm that constructs the Cliffords by layers * Added support for 1 qubits, for full sampling and for interleaved rb * Removed unused files. Black * Added 2 parameters to CliffordUtils.__init__: num_qubits and basis_gates * Removed all parameters num_qubits and use self.num-qubits instead * Removed usage of specific gate sets * moved interleaved element out of StandardRB * Split _build_rb_circuits into small methods to make it more modular * Added tests for CliffordUtils * Added support for cz * Added backend to CliffordInit.__init__. Added transpile to initial circuit created in _build methods * Modified test_correct_1q_depolarization for it to pass * black and pylint * Fixed bug with cz - since it is a symmetrical operation, we store only (cz, [0,1]) in all the Clifford lists. * Fixed the parameters in cliffordUtils methods. Since num_qubits was added as a class member, no need to pass it as a parameter. * Data updated by changes in create_clifford_map.py from previous commit * Fixed two tests. test_correct_1q_depolarization was failing due to too strict assertion. test_interleaving_circuit_with_delay needed to be changed because now returns transpiled circuits. * Changed usage of VGate and WGate to their component gates: s, h, sdg. * Moved transpiled clifford structures outside init to make them static in the class * Added test for two qubit rb in parallel * Moved structures back inside __init__ because the previous change caused a bug * Added back the old code to create RB circuits for more than 2 qubits * Changed InterleavedRB.circuits to call its super() when number of qubits > 2. Added default set of basis gates * Added test for three qubit RB * Documentation * black and pylint * Disabled black and pylint errors on clifford_data.py * Changed _clifford_utils to be a static class member. Added a couple of short methods to reduce code duplication * Updated release notes * Fixed failing test * Fixed bug: _transpile_cliff_layer_0 was ignoring the backend * Documentation * Reverted changes in tutorial as it is not mandatory to supply basis_gates any more * Cleaning up * Cleaning up * black and doc * Fixed bug found in tutorial - added transpile at the beginning of building an interleaved circuit * Added header * black * Cleaning up temporary comments * documentation * Changed order of several methods * Removed -interleave(). It was previously removed in main, but I forgot it in the code * Removed method _set_interleaved_element that was removed in a previous PR and I missed it * Name changed and spaces * Removed empty spaces * typo * Fixed transpilation of interleaved element. Made a few structural changes to the surrounding code
qiskit-community · Sep 21, 2022 · 0b15ccb · 0b15ccb
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diff --git a/qiskit_experiments/library/randomized_benchmarking/clifford_data.py b/qiskit_experiments/library/randomized_benchmarking/clifford_data.py
diff --git a/qiskit_experiments/library/randomized_benchmarking/clifford_utils.py b/qiskit_experiments/library/randomized_benchmarking/clifford_utils.py
diff --git a/qiskit_experiments/library/randomized_benchmarking/create_clifford_map.py b/qiskit_experiments/library/randomized_benchmarking/create_clifford_map.py
@@ -0,0 +1,253 @@
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+This is a script used to create the data in clifford_data.py.
+Every Clifford is represented by a number. We store a list of the compositions of Cliffords represented
+as numbers. For example, if Clifford1.compose(Clifford2) == Clifford3, then we conceptually,
+we store {(1, 2) : 3}. We don't actually store the map, but only the results of compose in a list,
+because this is more efficient in performance. The result is found using the indices of the input
+Cliffords.
+Similarly, we store for each number representing a Clifford, the number representing the
+inverse Clifford.
+For compose, we don't actually store the full compose table of all-cliffords X all-cliffords.
+Instead, we define an list of single-gate-cliffords. This comprises all Cliffords that consist
+of a single gate. There are 9 such Cliffords for 1-qubit, and 21 such Cliffords for 2-qubits.
+It is sufficient to store the compose table of all-cliffords X single-gate-cliffords,
+since for every Clifford on the right hand side, we can break it down into single gate Cliffords,
+and do the composition one gate at a time. This greatly reduces the storage space for the array of
+composition results (from O(n^2) to O(n)), where n is the number of Cliffords.
+"""
+import itertools
+
+from qiskit.circuit import QuantumCircuit
+from qiskit.circuit.library import (
+    IGate,
+    HGate,
+    SXdgGate,
+    SGate,
+    XGate,
+    SXGate,
+    YGate,
+    ZGate,
+    SdgGate,
+    CXGate,
+    CZGate,
+)
+from qiskit.quantum_info.operators.symplectic import Clifford
+from qiskit_experiments.library.randomized_benchmarking.clifford_utils import CliffordUtils
+
+gate_list_1q = [
+    IGate(),
+    HGate(),
+    SXdgGate(),
+    SGate(),
+    XGate(),
+    SXGate(),
+    YGate(),
+    ZGate(),
+    SdgGate(),
+]
+asymm_gates_2q = [
+    CXGate(),
+]
+symm_gates_2q = [CZGate()]
+
+
+class CliffordNumMapping:
+    """Class that creates creates all the structures with the mappings between Cliffords
+    and numbers."""
+
+    basis_gates = ["h", "s", "sdg", "x", "cx"]
+    single_gate_clifford_map_1q = {}
+    single_gate_clifford_map_2q = {}
+    num_to_cliff_1q = {}
+    cliff_to_num_1q = {}
+    num_to_cliff_2q = {}
+    cliff_to_num_2q = {}
+    layers_num_to_cliff_num_2q = {}
+    cliff_num_to_layers_2q = {}
+
+    @classmethod
+    def gen_nums_single_gate_cliffs_1q(cls):
+        """
+        Generates a dict mapping numbers to Cliffords and the reverse dict.
+        Based on these structures, we build a mapping from every single-gate-clifford to its number.
+        The mapping actually looks like {(gate, '[0]'): num}, where [0] represents qubit 0.
+        The qubit is added to be consistent with the format for 2 qubits.
+        """
+        clifford_utils = CliffordUtils(1, cls.basis_gates)
+        for i in range(clifford_utils.NUM_CLIFFORD_1_QUBIT):
+            cliff = clifford_utils.clifford_1_qubit(i)
+            cls.num_to_cliff_1q[i] = cliff
+            cls.cliff_to_num_1q[repr(cliff)] = i
+
+        for gate in gate_list_1q:
+            qc = QuantumCircuit(1)
+            qc.append(gate, [0])
+            cliff = Clifford(qc)
+            if repr(cliff) in cls.cliff_to_num_1q.keys():
+                num = cls.cliff_to_num_1q[repr(cliff)]
+                # qubit_as_str is not really necessary. It is only added to be consistent
+                # with the representation for 2 qubits
+                qubit_as_str = "[0]"
+                cls.single_gate_clifford_map_1q[(gate.name, qubit_as_str)] = num
+            else:
+                print("not found")
+        cliff_data_file.write(f"CLIFF_SINGLE_GATE_MAP_1Q = {cls.single_gate_clifford_map_1q}\n")
+
+    @classmethod
+    def gen_nums_single_gate_cliffs_2q(cls):
+        """
+        Generates a dict mapping numbers to Cliffords and the reverse dict.
+        Based on these structures, we build a mapping from every single-gate-clifford to its number.
+        The mapping actually looks like {(gate, '[qubits]'): num}.
+        """
+        clifford_utils = CliffordUtils(2, cls.basis_gates)
+        for i in range(clifford_utils.NUM_CLIFFORD_2_QUBIT):
+            cliff = clifford_utils.clifford_2_qubit(i)
+            cls.num_to_cliff_2q[i] = cliff
+            cls.cliff_to_num_2q[repr(cliff)] = i
+
+        for gate, qubit in itertools.product(gate_list_1q, [0, 1]):
+            qc = QuantumCircuit(2)
+            qc.append(gate, [qubit])
+            cliff = Clifford(qc)
+            if repr(cliff) in cls.cliff_to_num_2q:
+                num = cls.cliff_to_num_2q[repr(cliff)]
+                # qubit_as_str is not really necessary. It is only added to be consistent
+                # with the representation for 2 qubits
+                qubit_as_str = "[" + str(qubit) + "]"
+                cls.single_gate_clifford_map_2q[(gate.name, qubit_as_str)] = num
+            else:
+                print("not found")
+
+        for gate, qubits in itertools.product(asymm_gates_2q, [[0, 1], [1, 0]]):
+            qc = QuantumCircuit(2)
+            qc.append(gate, qubits)
+            cliff = Clifford(qc)
+            if repr(cliff) in cls.cliff_to_num_2q.keys():
+                num = cls.cliff_to_num_2q[repr(cliff)]
+            else:
+                print("not found")
+            direction = "[0, 1]" if qubits == [0, 1] else "[1, 0]"
+            cls.single_gate_clifford_map_2q[(gate.name, direction)] = num
+
+        for gate in symm_gates_2q:
+            qc = QuantumCircuit(2)
+            qc.append(gate, [0, 1])
+            cliff = Clifford(qc)
+            if repr(cliff) in cls.cliff_to_num_2q.keys():
+                num = cls.cliff_to_num_2q[repr(cliff)]
+            else:
+                print("not found")
+            cls.single_gate_clifford_map_2q[(gate.name, "[0, 1]")] = num
+
+        cliff_data_file.write(f"CLIFF_SINGLE_GATE_MAP_2Q = {cls.single_gate_clifford_map_2q}\n")
+
+    @classmethod
+    def create_compose_map_1q(cls):
+        """Creates the data in compose data in CLIFF_COMPOSE_DATA and
+        the inverse data in CLIFF_INVERSE_DATA"""
+        products = {}
+        for i in range(CliffordUtils.NUM_CLIFFORD_1_QUBIT):
+            cliff1 = cls.num_to_cliff_1q[i]
+            for gate in cls.single_gate_clifford_map_1q:
+                cliff2 = cls.num_to_cliff_1q[cls.single_gate_clifford_map_1q[gate]]
+                cliff = cliff1.compose(cliff2)
+                products[(i, gate)] = cls.cliff_to_num_1q[repr(cliff)]
+
+        invs = {}
+        for i in range(CliffordUtils.NUM_CLIFFORD_1_QUBIT):
+            cliff1 = cls.num_to_cliff_1q[i]
+            cliff = cliff1.adjoint()
+            invs[i] = cls.cliff_to_num_1q[repr(cliff)]
+
+        cliff_data_file.write("CLIFF_COMPOSE_DATA_1Q = [")
+        for i in products:
+            cliff_data_file.write(f"{products[i]},")
+        cliff_data_file.write("]")
+        cliff_data_file.write("\n")
+
+        cliff_data_file.write("CLIFF_INVERSE_DATA_1Q = [")
+        for i in invs:
+            cliff_data_file.write(f"{invs[i]},")
+        cliff_data_file.write("]")
+        cliff_data_file.write("\n")
+
+    @classmethod
+    def create_compose_map_2q(cls):
+        """Creates the data in CLIFF_COMPOSE_DATA and CLIFF_INVERSE_DATA"""
+        products = {}
+        for i in range(CliffordUtils.NUM_CLIFFORD_2_QUBIT):
+            cliff1 = cls.num_to_cliff_2q[i]
+            for gate in cls.single_gate_clifford_map_2q:
+                cliff2 = cls.num_to_cliff_2q[cls.single_gate_clifford_map_2q[gate]]
+                cliff = cliff1.compose(cliff2)
+                products[(i, gate)] = cls.cliff_to_num_2q[repr(cliff)]
+
+        invs = {}
+        for i in range(CliffordUtils.NUM_CLIFFORD_2_QUBIT):
+            cliff1 = cls.num_to_cliff_2q[i]
+            cliff = cliff1.adjoint()
+            invs[i] = cls.cliff_to_num_2q[repr(cliff)]
+
+        cliff_data_file.write("CLIFF_COMPOSE_DATA_2Q = [")
+        for i in products:
+            cliff_data_file.write(f"{products[i]},")
+        cliff_data_file.write("]")
+        cliff_data_file.write("\n")
+
+        cliff_data_file.write("CLIFF_INVERSE_DATA_2Q = [")
+        for i in invs:
+            cliff_data_file.write(f"{invs[i]},")
+        cliff_data_file.write("]")
+        cliff_data_file.write("\n")
+
+    @classmethod
+    def map_layers_to_cliffords_2q(cls):
+        """Creates a map from a triplet describing the indices in the layers, to the
+        number of the corresponding Clifford"""
+        clifford_utils = CliffordUtils(2, cls.basis_gates)
+        clifford_utils.transpile_2q_cliff_layers()
+        length = [len(clifford_utils._transpiled_cliff_layer[i]) for i in [0, 1, 2]]
+        for n0, n1, n2 in itertools.product(range(length[0]), range(length[1]), range(length[2])):
+            cliff = Clifford(clifford_utils.transpiled_cliff_from_layer_nums((n0, n1, n2)))
+
+            num = cls.cliff_to_num_2q[repr(cliff)]
+            cls.layers_num_to_cliff_num_2q[(n0, n1, n2)] = num
+            cls.cliff_num_to_layers_2q[num] = (n0, n1, n2)
+
+        cliff_data_file.write("CLIFF_LAYERS_TO_NUM_2Q = [")
+        for i in cls.layers_num_to_cliff_num_2q:
+            cliff_data_file.write(f"{cls.layers_num_to_cliff_num_2q[i]},")
+        cliff_data_file.write("]\n")
+
+        cliff_data_file.write("CLIFF_NUM_TO_LAYERS_2Q = [")
+        for i in range(len(cls.cliff_num_to_layers_2q)):
+            cliff_data_file.write(f"{cls.cliff_num_to_layers_2q[i]},")
+        cliff_data_file.write("]\n")
+
+    @classmethod
+    def create_clifford_data(cls):
+        """Creates all the data for compose and inverse."""
+        cls.gen_nums_single_gate_cliffs_1q()
+        cls.gen_nums_single_gate_cliffs_2q()
+        cls.create_compose_map_1q()
+        cls.create_compose_map_2q()
+
+
+with open("clifford_data.py", "w") as cliff_data_file:
+    cliff_data_file.write("# fmt: off\n")
+    cliff_data_file.write("# pylint: skip-file\n\n")
+    CliffordNumMapping.create_clifford_data()
+    CliffordNumMapping.map_layers_to_cliffords_2q()
+    cliff_data_file.write("\n# fmt: on\n")