fix equation doc

pina/equation/equation_interface.py

@@ -1,28 +1,23 @@
-"""Module for EquationInterface class"""
+"""Module for the Equation Interface"""
 
 from abc import ABCMeta, abstractmethod
 
 
 class EquationInterface(metaclass=ABCMeta):
     """
-    The abstract `AbstractProblem` class. All the class defining a PINA Problem
-    should be inheritied from this class.
-
-    In the definition of a PINA problem, the fundamental elements are:
-    the output variables, the condition(s), and the domain(s) where the
-    conditions are applied.
+    Abstract base class for equations.
     """
 
     @abstractmethod
     def residual(self, input_, output_, params_):
         """
-        Residual computation of the equation.
+        Abstract method to compute the residual of an equation.
 
-        :param LabelTensor input_: Input points to evaluate the equation.
-        :param LabelTensor output_: Output vectors given by my model (e.g.,
-        a ``FeedForward`` model).
-        :param dict params_: Dictionary of unknown parameters, eventually
-            related to an ``InverseProblem``.
-        :return: The residual evaluation of the specified equation.
+        :param LabelTensor input_: Input points where the equation is evaluated.
+        :param LabelTensor output_: Output tensor, eventually produced by a
+            :class:`~torch.nn.Module` instance.
+        :param dict params_: Dictionary of unknown parameters, associated with a
+            :class:`~pina.problem.InverseProblem` instance.
+        :return: The computed residual of the equation.
         :rtype: LabelTensor
         """