mirror_qv.py

mirror_qv.py

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+# Demonstrate mirror circuit simplification
+
+import math
+import random
+import sys
+import time
+
+from pyqrack import QrackSimulator, QrackCircuit
+
+
+def bench_qrack(n):
+    circ = QrackCircuit()
+
+    lcv_range = range(n)
+    all_bits = list(lcv_range)
+    x_op = [0, 1, 1, 0]
+    gateSequence = [ 0, 3, 2, 1, 2, 1, 0, 3 ]
+    row_len = math.ceil(math.sqrt(n))
+
+    for _ in lcv_range:
+        # Single-qubit gates
+        for i in lcv_range:
+            th = random.uniform(0, 2 * math.pi)
+            ph = random.uniform(0, 2 * math.pi)
+            lm = random.uniform(0, 2 * math.pi)
+            cos0 = math.cos(th / 2);
+            sin0 = math.sin(th / 2);
+            u_op = [
+                cos0 + 0j, sin0 * (-math.cos(lm) + -math.sin(lm) * 1j),
+                sin0 * (math.cos(ph) + math.sin(ph) * 1j), cos0 * (math.cos(ph + lm) + math.sin(ph + lm) * 1j)
+            ]
+            circ.mtrx(u_op, i)
+
+        # 2-qubit couplers
+        unused_bits = all_bits.copy()
+        random.shuffle(unused_bits)
+        while len(unused_bits) > 1:
+            circ.ucmtrx([unused_bits.pop()], x_op, unused_bits.pop(), 1)
+
+    # Dig into the (open source) code for yourself:
+    # Qrack does NOT have a special-case optimization
+    # when appending specifically the circuit inverse;
+    # it just simplifies to identity, gate-by-gate.
+    # (This is not necessarily true for every possible
+    # "mirror circuit," i.e. any circuit that
+    # simplifies to identity operator.)
+    start = time.perf_counter()
+    sim = QrackSimulator(n)
+    circ.run(sim)
+    circ.inverse().run(sim)
+    if sim.m_all() != 0:
+        raise Exception("Mirror circuit failed!")
+    seconds = time.perf_counter() - start
+    fidelity = sim.get_unitary_fidelity()
+
+    return (seconds, fidelity)
+
+
+def main():
+    n = 50
+    if len(sys.argv) > 1:
+        n = int(sys.argv[1])
+
+    results = bench_qrack(n)
+
+    print(n, "qubits,",
+        results[0], "seconds,",
+        results[1], "fidelity"
+    )
+
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())