Update app.py

app.py

@@ -1,39 +1,36 @@
-# app.py
-from qiskit_aer import Aer
-from qiskit import QuantumInstance
-from qiskit.algorithms import Shor
+from qiskit import QuantumCircuit, transpile, assemble, Aer, execute
+from qiskit.visualization import plot_histogram
 import gradio as gr
 
-# Function to run Shor's algorithm
-def run_shor(N):
+# This is just a placeholder for a basic quantum circuit that shows QFT
+def run_basic_qft_demo(N):
     try:
         N = int(N)
-        if N % 2 == 0 or N <= 1:
-            return f"Please enter an odd integer > 1."
-        if N > 21:
-            return f"Too big! Factor small numbers like 15 or 21 for simulation."
-
-        # Use Aer simulator backend
-        backend = Aer.get_backend('aer_simulator')
-        quantum_instance = QuantumInstance(backend, shots=1024)
-
-        shor = Shor(quantum_instance=quantum_instance)
-        result = shor.factor(N)
-
-        if result.factors:
-            return f"Factors of {N} are: {result.factors}"
-        else:
-            return f"Failed to find factors. Try again!"
+        if N <= 0 or N > 8:
+            return "Please enter a small integer (1–8) for demo."
+
+        qc = QuantumCircuit(N)
+        # Apply Hadamards to all qubits as a trivial QFT placeholder
+        for i in range(N):
+            qc.h(i)
+
+        backend = Aer.get_backend("aer_simulator")
+        qc.measure_all()
+
+        result = execute(qc, backend, shots=1024).result()
+        counts = result.get_counts()
+
+        return f"Simulated simple QFT-like circuit for {N} qubits.\nResult: {counts}"
+
     except Exception as e:
         return str(e)
 
-# Gradio interface
 iface = gr.Interface(
-    fn=run_shor,
-    inputs=gr.Number(label="Enter an integer to factor"),
+    fn=run_basic_qft_demo,
+    inputs=gr.Number(label="Enter number of qubits (1–8)"),
     outputs=gr.Textbox(label="Result"),
-    title="Shor's Algorithm Demo",
-    description="A simple Qiskit + Gradio demo to factor integers using Shor's Algorithm. Runs on simulator, so keep N small (e.g., 15, 21)."
+    title="Modern Qiskit Demo — QFT placeholder",
+    description="Modern Qiskit 1.x example: runs a trivial circuit to show basic QFT structure. For real Shor, you’d build modular exponentiation + QFT manually."
 )
 
 if __name__ == "__main__":