Update tutorial 1,3,4,9 plots

Author: MatteB03

tutorials/tutorial1/tutorial.ipynb

@@ -38,7 +38,7 @@
 # 
 # ```python
 # from pina.problem import SpatialProblem
-# from pina.geometry import CartesianProblem
+# from pina.domain import CartesianProblem
 # 
 # class SimpleODE(SpatialProblem):
 #     
@@ -233,7 +233,6 @@ def truth_solution(self, pts):
 
 # inspecting final loss
 trainer.logged_metrics
-print(type(problem.truth_solution))
 
 
 # By using `matplotlib` we can also do some qualitative plots of the solution. 
@@ -260,7 +259,6 @@ def truth_solution(self, pts):
             idx for idx, s in enumerate(trainer.callbacks)
             if isinstance(s, MetricTracker)
         ]
-print(list_[0])
 trainer_metrics = trainer.callbacks[list_[0]].metrics
 
 loss = trainer_metrics['val_loss']