---
jupytext:
  formats: ipynb,md:myst
  text_representation:
    extension: .md
    format_name: myst
    format_version: 0.13
    jupytext_version: 1.17.3
kernelspec:
  display_name: festim-workshop
  language: python
  name: python3
---

# Using the HTM database

+++

FESTIM can be coupled to the hydrogen transport properties database [HTM](https://github.com/RemDelaporteMathurin/h-transport-materials).

H-transport-materials (HTM) is a python library for accessing hydrogen transport properties such as diffusivities, solubilities, recombination coefficients, etc. HTM is open-source and contributions to the database are more than welcome! See the online dashboard __[here](https://htm-dashboard-uan5l4xr6a-od.a.run.app/)__!

Objectives:
* Learn how to install and use the HTM library
* Learn how to use and integrate HTM in FESTIM

+++

## Using the HTM Property Database ##

First, install HTM by running: 

` pip install h-transport-materials `

Now that HTM is installed, let's look at at the HTM API.

The diffusivities in the HTM database are stored in ` htm.diffusivities `. They can be filtered by material, isotope, author, year with the ` .filter() ` method. 

Let's plot the different diffusivities for tungsten:

```{code-cell} ipython3
import h_transport_materials as htm

# filter only tungsten and H
diffusivities = htm.diffusivities.filter(material="tungsten").filter(isotope="h")

# plot the properties
htm.plotting.plot(diffusivities)

import matplotlib.pyplot as plt

plt.yscale("log")
plt.ylabel("Diffusivity (m$^2$/s)")
plt.legend()
plt.show()
```

Now let's take a look at the different solubilities for tungsten:

```{code-cell} ipython3
plt.figure()
# filter only tungsten and H
solubilities = htm.solubilities.filter(material="tungsten")

htm.plotting.plot(solubilities)


plt.yscale("log")
plt.ylabel("Solubility")
plt.legend()
plt.show()
```

## Integrating with FESTIM ##

To use HTM in FESTIM, we should first specify an author to get specific material properties. For example, let's look at tungsten properties from Frauenfelder. We can filter the properties with `.filter(author="frauenfelder")`, obtaining a single `htm.ArrheniusProperty object`:

```{code-cell} ipython3
diffusivities = htm.diffusivities.filter(material="tungsten").filter(isotope="h").filter(author="frauenfelder")
D = diffusivities[0]

print(type(diffusivities))
print(type(D))
```

A `htm.ArrheniusProperty` object has several useful attributes like `.pre_exp` which holds the pre-exponential factor, `.act_energy` for the activation energy but also `.author` and `.year`:

```{code-cell} ipython3
print(D)
```

We can also look at the solubility:

```{code-cell} ipython3
S = htm.solubilities.filter(material="tungsten").filter(author="frauenfelder")[0]
print(S)
```

These properties can then be used inside a `FESTIM.Material` object. This is extremely useful to avoid silly copy-pasting mistakes and typos in simulations.

```{code-cell} ipython3
import festim as F

tungsten = F.Material(
    D_0=D.pre_exp.magnitude, E_D=D.act_energy.magnitude,
    K_S_0=S.pre_exp.magnitude, E_K_S=S.act_energy.magnitude
    )

print(tungsten.D_0, tungsten.E_D)
```