Add docstrings to the maxpool2d module

Author: milancurcic

src/nf_maxpool2d_layer.f90

@@ -33,28 +33,41 @@ module nf_maxpool2d_layer
 
   interface maxpool2d_layer
     pure module function maxpool2d_layer_cons(pool_size, stride) result(res)
+      !! `maxpool2d` constructor function
       integer, intent(in) :: pool_size
+        !! Width and height of the pooling window
       integer, intent(in) :: stride
+        !! Stride of the pooling window
       type(maxpool2d_layer) :: res
     end function maxpool2d_layer_cons
   end interface maxpool2d_layer
 
   interface
 
     module subroutine init(self, input_shape)
+      !! Initialize the `maxpool2d` layer instance with an input shape.
       class(maxpool2d_layer), intent(in out) :: self
+        !! `maxpool2d_layer` instance
       integer, intent(in) :: input_shape(:)
+        !! Array shape of the input layer
     end subroutine init
 
     pure module subroutine forward(self, input)
+      !! Run a forward pass of the `maxpool2d` layer.
       class(maxpool2d_layer), intent(in out) :: self
+        !! `maxpool2d_layer` instance
       real, intent(in) :: input(:,:,:)
+        !! Input data (output of the previous layer)
     end subroutine forward
 
     module subroutine backward(self, input, gradient)
+      !! Run a backward pass of the `maxpool2d` layer.
       class(maxpool2d_layer), intent(in out) :: self
+        !! `maxpool2d_layer` instance
       real, intent(in) :: input(:,:,:)
+        !! Input data (output of the previous layer)
       real, intent(in) :: gradient(:,:,:)
+        !! Gradient from the downstream layer
     end subroutine backward
 
   end interface