feat(qft): add qft generation script

qft.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python3
+# /// script
+# requires-python = ">=3.13"
+# dependencies = [
+#     "qiskit[visualization]",
+# ]
+# ///
+"""Grover's Algorithm Visualizer A script to demonstrate and visualize Grover's
+quantum search algorithm."""
+
+from argparse import ArgumentParser, Namespace
+from math import pi
+from typing import cast
+
+from qiskit import QuantumCircuit
+
+
+def create_manual_qft_circuit(n_qubits: int) -> QuantumCircuit:
+    """Create QFT circuit manually to show individual gates.
+
+    Args:
+        n_qubits (int): Number of qubits for the QFT
+
+    Returns:
+        QuantumCircuit: QFT circuit
+    """
+    qc = QuantumCircuit(n_qubits)
+
+    for i in range(n_qubits):
+        qc.h(i)
+
+        for j in range(i + 1, n_qubits):
+            angle = cast("float", 2 * pi / (2 ** (j - i + 1)))
+            qc.cp(angle, j, i)
+
+    for i in range(n_qubits // 2):
+        qc.swap(1, n_qubits - 1 - i)
+
+    return qc
+
+
+def parse_args() -> Namespace:
+    parser = ArgumentParser(description="Generate and display Quantum Fourier Transform circuits")
+    parser.add_argument(
+        "n_qubits",
+        type=int,
+        help="Number of qubits for the QFT circuit (must be positive)",
+    )
+    parser.add_argument(
+        "--show-stats",
+        action="store_true",
+        default=True,
+        help="Show circuit statistics (default: True)",
+    )
+    parser.add_argument(
+        "--no-stats",
+        action="store_true",
+        help="Hide circuit statistics",
+    )
+    return parser.parse_args()
+
+
+def validate_input(n_qubits: int) -> bool:
+    """Validate the number of qubits input.
+
+    Args:
+        n_qubits (int): Number of qubits to validate
+
+    Returns:
+        bool: True if valid, False otherwise
+    """
+    if n_qubits <= 0:
+        print("Error: Number of qubits must be positive")
+        return False
+
+    if n_qubits > 10:
+        print(
+            f"Warning: {n_qubits} qubits will create a large circuit. Consider using fewer qubits for better visualization."
+        )
+
+    return True
+
+
+def display_circuit_info(circuit: QuantumCircuit, n_qubits: int) -> None:
+    """Display circuit information and statistics.
+
+    Args:
+        circuit (QuantumCircuit): The QFT circuit to display
+        n_qubits (int): Number of qubits in the circuit
+    """
+    print(f"Quantum Fourier Transform for {n_qubits} qubits\n")
+    print(circuit.draw())
+
+
+def display_statistics(circuit: QuantumCircuit) -> None:
+    """Display circuit statistics.
+
+    Args:
+        circuit (QuantumCircuit): The circuit to analyze
+    """
+    print("\nCircuit Statistics:")
+    print(f"Depth: {circuit.depth()}")
+    print(f"Gate count: {len(circuit.data)}")
+
+
+def main() -> None:
+    """Main function to orchestrate the QFT circuit generation and display."""
+    args = parse_args()
+    n_qubits = cast("int", args.n_qubits)
+
+    if not validate_input(n_qubits):
+        return
+
+    manual_qft_circuit = create_manual_qft_circuit(n_qubits)
+    display_circuit_info(manual_qft_circuit, n_qubits)
+
+    show_stats = cast("bool", args.show_stats) and not cast("bool", args.no_stats)
+    if show_stats:
+        display_statistics(manual_qft_circuit)
+
+
+if __name__ == "__main__":
+    main()