Running DeepMD-Kit with Pharmaforge
====================================

The goal of this tutorial is to demonstrate the use of the `pharmaforge` package in conjunction with `dftb+` and `deepmd-kit` to take a query from the database (see the previous example on database querying.

Learning Objectives
-------------------
- Learn hopw to use the `pharmaforge` package to run a deep potential on queried configurations from the database.
- Learn how to use the dftb+ package to run a DFTB calculation on queried configurations from the database using `pharmaforge`.
- Calculate the correction energy using the QDPi1 model.

Required Files
--------------
- The tutorial python script is located in examples/CalculateMLP
- The QDPi1 deepmd-kit model is located at `https://gitlab.com/RutgersLBSR/qdpi`, and should be downloaded into inputs.
- DFTB+ should be installed (https://dftbplus.github.io/).
- DFTB+ slater-Koster files must be downloaded somewhere. The path to these files should be pointed to within the run_qdpi1.py script.

Tutorial
--------

First thing, make sure all the required files are in the correct location (See above) and that DFTB+ is installed.

Then, set the skf file locations as follows (or putting them into this location):

.. literalinclude:: ../../../../examples/CalculateMLP/run_qdpi1.py
    :language: python
    :end-at: skf_location=

Now, we will first calculate the deep potential energy using the QDPi1 model, which if you recall is a deepmd-kit :math:`\Delta MLP` model. The script to do this is as follows:

.. literalinclude:: ../../../../examples/CalculateMLP/run_qdpi1.py
    :language: python
    :start-at: Test DeepMdKit
    :end-before: Test DFTB3

As with the previous examples, you will see the energies and forces printed out. 

Next, we will calculate the DFTB energy using the dftb+ package. The script to do this is as follows:

.. literalinclude:: ../../../../examples/CalculateMLP/run_qdpi1.py
    :language: python
    :start-at: Test DFTB3
    :end-at: print(energies)

Now, for a :math:`\Delta MLP` the higher level potential energy is described by the following 

.. math:: E_{higher level} = E_{MLP} + E_{DFTB}
    :label: eq:MLP_DFTB

So, we can calcualte the correction energy as follows:

.. literalinclude:: ../../../../examples/CalculateMLP/run_qdpi1.py
    :language: python
    :start-after: print(energies)


Note that these numbers are very similar to the numbers you found during your data_labeling tutorial!

Full Code
---------

.. literalinclude:: ../../../../examples/CalculateMLP/run_qdpi1.py
    :language: python