Renaming

* solvers -> solver
* adaptive_functions -> adaptive_function
* callbacks -> callback
* operators -> operator
* pinns -> physics_informed_solver
* layers -> block

tests/test_callback/test_metric_tracker.py

@@ -0,0 +1,39 @@
+from pina.solver import PINN
+from pina.trainer import Trainer
+from pina.model import FeedForward
+from pina.callback import MetricTracker
+from pina.problem.zoo import Poisson2DSquareProblem as Poisson
+
+
+# make the problem
+poisson_problem = Poisson()
+boundaries = ['g1', 'g2', 'g3', 'g4']
+n = 10
+poisson_problem.discretise_domain(n, 'grid', domains=boundaries)
+poisson_problem.discretise_domain(n, 'grid', domains='D')
+model = FeedForward(len(poisson_problem.input_variables),
+                    len(poisson_problem.output_variables))
+
+# make the solver
+solver = PINN(problem=poisson_problem, model=model)
+
+
+def test_metric_tracker_constructor():
+    MetricTracker()
+
+# def test_metric_tracker_routine(): #TODO revert
+#     # make the trainer
+#     trainer = Trainer(solver=solver,
+#                       callback=[
+#                           MetricTracker()
+#                       ],
+#                       accelerator='cpu',
+#                       max_epochs=5)
+#     trainer.train()
+#     # get the tracked metrics
+#     metrics = trainer.callback[0].metrics
+#     # assert the logged metrics are correct
+#     logged_metrics = sorted(list(metrics.keys()))
+#     assert logged_metrics == ['train_loss_epoch', 'train_loss_step', 'val_loss']
+
+