.. role:: python(code)
   :language: python



..
    `  <>`

.. _`sec:back_to_pinn`:


Back to PINNs
~~~~~~~~~~~~~


All the ingredients are ready for a basic implementation of a PINN solver. 
The goal of this section is to gradually build and test this solver. 
A structure very similar to the one used for the FNN implementation is used. 

The :python:`LayerNode` class:

.. literalinclude:: ../../../../../../src/ai/fnn/pinn_vectorized.py
      :pyobject: LayerNode
      :name: LayerNode
      :linenos:       
      :caption: src 

Let us focus on the modfication :python:`FNN` class into the :python:`PINN` class. 
Most of the new code appears in the losses and gradient calculations.

.. admonition:: Exercise (intermediate)

    Implement and test the suggested methods.

    .. literalinclude:: ../../../../../../src/ai/fnn/pinn_vectorized_empty.py
        :pyobject: PINN
        :name: PINN
        :linenos:       
        :caption: src