updated the EM UI to show the nearest position message for IBM QPU/Statevector Estimator Output Preference

em/qpu.py

@@ -55,41 +55,32 @@ def hide_qpu_plots():
 
 
 def update_qpu_sample_slot(slot: int):
-    """Update QPU sample slot with grid point info."""
+    """Update QPU sample slot with grid point info and nearest position message."""
     try:
-        samples_var = f"qpu_monitor_samples{'_' + str(slot) if slot > 1 else ''}"
-        info_var = f"qpu_monitor_sample_info{'_' + str(slot) if slot > 1 else ''}"
-        gp_var = f"qpu_monitor_gridpoints{'_' + str(slot) if slot > 1 else ''}"
+        suffix = "" if slot == 1 else f"_{slot}"
+        samples_var = f"qpu_monitor_samples{suffix}"
+        info_var = f"qpu_monitor_sample_info{suffix}"
+        gp_var = f"qpu_monitor_gridpoints{suffix}"
         
         samples = getattr(state, samples_var, "")
-        nx = int(state.nx or 16)
         
-        if not samples:
+        if not samples or not str(samples).strip():
             setattr(state, info_var, "")
             setattr(state, gp_var, "")
             return
-            
-        # Parse sample pairs
-        pairs = re.findall(r'\(\s*([-+]?\d*\.?\d+)\s*,\s*([-+]?\d*\.?\d+)\s*\)', str(samples))
-        if not pairs:
-            setattr(state, info_var, "Invalid format. Use (x, y).")
+        
+        nx_val = state.nx
+        if nx_val is None:
+            setattr(state, info_var, "Select a grid size (nx) to compute the nearest grid position.")
             setattr(state, gp_var, "")
             return
-            
-        gps = []
-        labels = []
-        for x_str, y_str in pairs:
-            x = float(x_str)
-            y = float(y_str)
-            i = int(round(x * (nx - 1)))
-            j = int(round(y * (nx - 1)))
-            i = max(0, min(nx - 1, i))
-            j = max(0, min(nx - 1, j))
-            gps.append((i, j))
-            labels.append(f"({i}, {j})")
-            
-        setattr(state, gp_var, "; ".join(labels))
-        setattr(state, info_var, f"Grid points: {', '.join(labels)}")
+        
+        # Import snap_samples_to_grid to get consistent position formatting
+        from .excitation import snap_samples_to_grid
+        
+        snapped, message = snap_samples_to_grid(samples, int(nx_val))
+        setattr(state, gp_var, snapped)
+        setattr(state, info_var, message or "")
     except Exception:
         pass