Delayed model P1 initialization

predtuner/modeledapp.py

@@ -200,7 +200,7 @@ class QoSModelP1(IQoSModel):
         self.delta_tensors = {
             op: {k.name: None for k in self.app.knobs} for op in self.app.ops
         }
-        self.baseline_tensor = self.output_f({})
+        self.baseline_tensor = None
 
     @property
     def name(self) -> str:
@@ -218,7 +218,7 @@ class QoSModelP1(IQoSModel):
 
     def _init(self):
         dt = self.delta_tensors
-        btensor = self.baseline_tensor
+        btensor = self.baseline_tensor = self.output_f({})
         if self.storage and self.storage.is_file():
             for op, knob, delta_tensor in self._load(self.storage):
                 dt[op][knob] = delta_tensor