minor fix

pina/problem/abstract_problem.py

@@ -18,9 +18,32 @@ class AbstractProblem(metaclass=ABCMeta):
 
         return variables
 
+    @property
+    def domain(self):
+
+        domains = [
+            getattr(self, f'{t}_domain')
+            for t in ['spatial', 'temporal', 'parameter']
+            if hasattr(self, f'{t}_domain')
+        ]
+
+        if len(domains) == 1:
+            return domains[0]
+        elif len(domains) == 0:
+            raise RuntimeError
+
+        if len(set(map(type, domains))) == 1:
+            domain = domains[0].__class__({})
+            [domain.update(d) for d in domains]
+            return domain
+        else:
+            raise RuntimeError('different domains')
+
+
+
     @input_variables.setter
     def input_variables(self, variables):
-        raise NotImplementedError
+        raise RuntimeError
 
     @property
     @abstractmethod

pina/problem/parametric_problem.py

@@ -5,7 +5,10 @@ from .abstract_problem import AbstractProblem
 
 class ParametricProblem(AbstractProblem):
 
-    @property
     @abstractmethod
-    def parameters(self):
+    def parameter_domain(self):
         pass
+
+    @property
+    def parameters(self):
+        return self.parameter_domain.variables

pina/problem/spatial_problem.py

@@ -6,5 +6,9 @@ from .abstract_problem import AbstractProblem
 class SpatialProblem(AbstractProblem):
 
     @abstractmethod
-    def spatial_variables(self):
+    def spatial_domain(self):
         pass
+
+    @property
+    def spatial_variables(self):
+        return self.spatial_domain.variables

pina/problem/timedep_problem.py

@@ -5,7 +5,10 @@ from .abstract_problem import AbstractProblem
 
 class TimeDependentProblem(AbstractProblem):
 
-    @property
     @abstractmethod
-    def temporal_variable(self):
+    def temporal_domain(self):
         pass
+
+    @property
+    def temporal_variables(self):
+        return self.temporal_domain.variables