minor fix, add few tests (#38)

pina/pinn.py

@@ -45,7 +45,7 @@ class PINN(object):
         self.device = torch.device(device)
 
         self.dtype = dtype
-        self.history = []
+        self.history_loss = {}
 
         self.model = model
         self.model.to(dtype=self.dtype, device=self.device)
@@ -92,7 +92,7 @@ class PINN(object):
                 'model_state': self.model.state_dict(),
                 'optimizer_state' : self.optimizer.state_dict(),
                 'optimizer_class' : self.optimizer.__class__,
-                'history' : self.history,
+                'history' : self.history_loss,
                 'input_points_dict' : self.input_pts,
         }
 
@@ -113,7 +113,7 @@ class PINN(object):
         self.optimizer.load_state_dict(checkpoint['optimizer_state'])
 
         self.trained_epoch = checkpoint['epoch']
-        self.history = checkpoint['history']
+        self.history_loss = checkpoint['history']
 
         self.input_pts = checkpoint['input_points_dict']
 
@@ -184,7 +184,7 @@ class PINN(object):
             self.input_pts[location].requires_grad_(True)
             self.input_pts[location].retain_grad()
 
-    def train(self, stop=100, frequency_print=2, trial=None):
+    def train(self, stop=100, frequency_print=2, save_loss=1, trial=None):
 
         epoch = 0
 
@@ -230,10 +230,9 @@ class PINN(object):
             sum(losses).backward()
             self.optimizer.step()
 
-            self.trained_epoch += 1
+            if save_loss and (epoch % save_loss == 0 or epoch == 0):
-            if epoch % 50 == 0:
+                self.history_loss[epoch] = [
-                self.history.append([loss.detach().item() for loss in losses])
+                    loss.detach().item() for loss in losses]
-            epoch += 1
 
             if trial:
                 import optuna
@@ -245,7 +244,7 @@ class PINN(object):
                 if epoch == stop:
                     print('[epoch {:05d}] {:.6e} '.format(self.trained_epoch, sum(losses).item()), end='')
                     for loss in losses:
-                        print('{:.6e} '.format(loss), end='')
+                        print('{:.6e} '.format(loss.item()), end='')
                     print()
                     break
             elif isinstance(stop, float):
@@ -260,9 +259,12 @@ class PINN(object):
 
                 print('[epoch {:05d}] {:.6e} '.format(self.trained_epoch, sum(losses).item()), end='')
                 for loss in losses:
-                    print('{:.6e} '.format(loss), end='')
+                    print('{:.6e} '.format(loss.item()), end='')
                 print()
 
+            self.trained_epoch += 1
+            epoch += 1
+
         return sum(losses).item()
 
 

pina/plotter.py

@@ -131,3 +131,22 @@ class Plotter:
             plt.savefig(filename)
         else:
             plt.show()
+
+    def plot_loss(self, pinn, label=None, log_scale=True):
+        """
+        Plot the loss trend
+
+        TODO
+        """
+
+        if not label:
+            label = str(pinn)
+
+        epochs = list(pinn.history_loss.keys())
+        loss = np.array(list(pinn.history_loss.values()))
+        if loss.ndim != 1:
+            loss = loss[:, 0]
+
+        plt.plot(epochs, loss, label=label)
+        if log_scale:
+            plt.yscale('log')

pina/span.py

@@ -56,7 +56,6 @@ class Span(Location):
     def sample(self, n, mode='random', variables='all'):
         """TODO
         """
-
         def _1d_sampler(n, mode, variables):
             """ Sample independentely the variables and cross the results"""
             tmp = []

tests/test_pinn.py

@@ -38,8 +38,8 @@ class Poisson(SpatialProblem):
     truth_solution = poisson_sol
 
 problem = Poisson()
-model = FeedForward(2, 1)
 
+model = FeedForward(problem.input_variables, problem.output_variables)
 
 def test_constructor():
     PINN(problem, model)
@@ -59,3 +59,23 @@ def test_span_pts():
     assert pinn.input_pts['D'].shape[0] == n**2
     pinn.span_pts(n, 'random', locations=['D'])
     assert pinn.input_pts['D'].shape[0] == n
+
+def test_train():
+    pinn = PINN(problem, model)
+    boundaries = ['gamma1', 'gamma2', 'gamma3', 'gamma4']
+    n = 10
+    pinn.span_pts(n, 'grid', boundaries)
+    pinn.span_pts(n, 'grid', locations=['D'])
+    pinn.train(5)
+
+def test_train():
+    boundaries = ['gamma1', 'gamma2', 'gamma3', 'gamma4']
+    n = 10
+    expected_keys = [[], list(range(0, 50, 3))]
+    param = [0, 3]
+    for i, truth_key in zip(param, expected_keys):
+        pinn = PINN(problem, model)
+        pinn.span_pts(n, 'grid', boundaries)
+        pinn.span_pts(n, 'grid', locations=['D'])
+        pinn.train(50, save_loss=i)
+        assert list(pinn.history_loss.keys()) == truth_key