[WIP] Normalize flow_rate profiles before fitting

CADETProcess/processModel/process.py

@@ -652,17 +652,35 @@ def add_flow_rate_profile(self, unit, time, flow_rate, s=1e-6):
         if max(time) > self.cycle_time:
             raise ValueError('Inlet profile exceeds cycle time')
 
-        tck = interpolate.splrep(time, flow_rate, s=s)
+        # Compute min and max for scaling
+        min_val = np.min(flow_rate)
+        max_val = np.max(flow_rate)
+        range_val = max_val - min_val
+
+        if range_val == 0:
+            raise ValueError('Flow rate has no variation; cannot scale.')
+
+        # Normalize flow_rate to [0, 1]
+        normalized_flow_rate = (flow_rate - min_val) / range_val
+
+        # Fit the spline with normalized flow_rate
+        tck = interpolate.splrep(time, normalized_flow_rate, s=s)
         ppoly = interpolate.PPoly.from_spline(tck)
 
+        # Add events with unscaled coefficients
         for i, (t, sec) in enumerate(zip(ppoly.x, ppoly.c.T)):
             if i < 3:
                 continue
             elif i > len(ppoly.x) - 5:
                 continue
-            evt = self.add_event(
+
+            # Unscale all coefficients
+            unscaled_sec = sec * range_val
+            # Adjust the constant term (last coefficient in the array) for shifting
+            unscaled_sec[-1] += min_val
+            self.add_event(
                 f'{unit}_flow_rate_{i-3}', f'flow_sheet.{unit}.flow_rate',
-                np.flip(sec), t
+                np.flip(unscaled_sec), t
             )
 
     def check_config(self):