refactor: make subfiles

src/grovers_visualizer/main.py

@@ -0,0 +1,120 @@
+#!/usr/bin/env python
+"""Grover's Algorithm Visualizer.
+
+This script builds a Grover search circuit based on user input, runs the
+simulation using Qiskit's Aer simulator, and visualizes the results
+using matplotlib.
+"""
+
+from itertools import product
+
+import matplotlib.pyplot as plt
+import numpy as np
+from matplotlib.axes import Axes
+from qiskit import QuantumCircuit
+from qiskit_aer import AerSimulator
+
+
+def x(qc: QuantumCircuit, target_state: str) -> None:
+    for i, bit in enumerate(reversed(target_state)):
+        if bit == "0":
+            qc.x(i)
+
+
+def ccz(qc: QuantumCircuit, n: int) -> None:
+    """Multi-controlled Z (for 3 qubits, this is a CCZ)"""
+    if n == 1:
+        qc.z(0)
+    elif n == 2:
+        qc.cz(0, 1)
+    else:
+        qc.h(n - 1)
+        qc.mcx(list(range(n - 1)), n - 1)  # multi-controlled X (Toffoli for 3 qubits)
+        qc.h(n - 1)
+
+
+def oracule(qc: QuantumCircuit, target_state: str) -> None:
+    n = len(target_state)
+
+    x(qc, target_state)
+
+    ccz(qc, n)
+
+    # Undo the X gates
+    x(qc, target_state)
+
+
+def diffusion(qc: QuantumCircuit, n: int) -> None:
+    """Apply the Grovers diffusion operator"""
+
+    qc.h(range(n))
+    qc.x(range(n))
+
+    ccz(qc, n)
+
+    qc.x(range(n))
+    qc.h(range(n))
+
+
+def grover_search(n: int, target_state: str) -> QuantumCircuit:
+    qc = QuantumCircuit(n, n)
+
+    qc.h(range(n))
+
+    num_states = 2**n
+
+    iterations = int(np.floor(np.pi / 4 * np.sqrt(num_states)))
+    for _ in range(iterations):
+        oracule(qc, target_state)
+        diffusion(qc, n)
+
+    qc.measure(range(n), range(n))
+    return qc
+
+
+def plot_counts(ax: Axes, counts: dict[str, int], target_state: str) -> None:
+    """Create and display a bar chart for the measurement results."""
+
+    # Sort the states
+    states = list(counts.keys())
+    frequencies = [counts[s] for s in states]
+
+    ax.clear()
+    ax.bar(states, frequencies, color="skyblue")
+    ax.set_xlabel("Measured State")
+    ax.set_ylabel("Counts")
+    ax.set_title(f"Measurement Counts for Target: {target_state}")
+    ax.set_ylim(0, max(frequencies) * 1.2)
+
+
+def main() -> None:
+    n_qubits = 3
+    combinations = product(["0", "1"], repeat=n_qubits)
+    states = ["".join(x) for x in combinations]
+    shots = 1024
+
+    _, ax = plt.subplots(figsize=(8, 4))
+    plt.ion()
+
+    for state in states:
+        qc = grover_search(n_qubits, state)
+
+        print(qc.draw("text"))
+
+        simulator = AerSimulator()
+        job = simulator.run(qc, shots=shots)
+        result = job.result()
+        counts: dict[str, int] = result.get_counts(qc)
+        sorted_counts = dict(sorted(counts.items(), key=lambda x: x[1], reverse=True))
+
+        print(f"Target: {state}")
+        print("\n".join(f"'{k}': {v}" for k, v in sorted_counts.items()))
+
+        plot_counts(ax, sorted_counts, state)
+        plt.pause(1)
+
+    plt.show()
+
+
+if __name__ == "__main__":
+    main()