Fix bug in add_points method

* solving `add_points`

---------

Co-authored-by: Gabriele Codega <gcodega@pascal.maths.sissa.it>

pina/problem/abstract_problem.py

@@ -273,7 +273,7 @@ class AbstractProblem(metaclass=ABCMeta):
                 new_pts.labels = old_pts.labels
 
             # merging
-            merged_pts = torch.vstack([old_pts, new_points[location]])
+            merged_pts = torch.vstack([old_pts, new_pts])
             merged_pts.labels = old_pts.labels
             self.input_pts[location] = merged_pts
 

tests/test_problem.py

@@ -131,3 +131,14 @@ def test_variables_correct_order_sampling():
                                       variables=['x'])
     assert poisson_problem.input_pts['D'].labels == sorted(
         poisson_problem.input_variables)
+
+def test_add_points():
+    poisson_problem = Poisson()
+    poisson_problem.discretise_domain(0,
+                                      'random',
+                                      locations=['D'],
+                                      variables=['x','y'])
+    new_pts = LabelTensor(torch.tensor([[0.5,-0.5]]),labels=['x','y'])
+    poisson_problem.add_points({'D': new_pts})
+    assert torch.isclose(poisson_problem.input_pts['D'].extract('x'),new_pts.extract('x'))
+    assert torch.isclose(poisson_problem.input_pts['D'].extract('y'),new_pts.extract('y'))