# SciANN: Neural Networks for Scientific Computations

## New to SciANN?

SciANN is a high-level artificial neural networks API, written in Python using Keras and TensorFlow backends. It is developed with a focus on enabling fast experimentation with different networks architectures and with emphasis on scientific computations, physics informed deep learing, and inversion. *Being able to start deep-learning in a very few lines of code is key to doing good research.*

Use SciANN if you need a deep learning library that:

- Allows for easy and fast prototyping.
- Allows the use of complex deep neural networks.
- Takes advantage TensorFlow and Keras features including seamlessly running on CPU and GPU.

For more details, check out our review paper at https://arxiv.org/abs/2005.08803 and the documentation at SciANN.com.

Have questions or would like to contribute, please join sciann.slack.com.

Cite SciANN in your publications if it helps your research:

```
@article{haghighat2020sciann,
title = {SciANN: A Keras/TensorFlow wrapper for scientific computations and physics-informed deep learning using artificial neural networks},
journal = {Computer Methods in Applied Mechanics and Engineering},
volume = {373},
pages = {113552},
year = {2021},
issn = {0045-7825},
doi = {https://doi.org/10.1016/j.cma.2020.113552},
url = {https://www.sciencedirect.com/science/article/pii/S0045782520307374},
author = {Ehsan Haghighat and Ruben Juanes},
keywords = {SciANN, Deep neural networks, Scientific computations, PINN, vPINN},
}
```

SciANN is compatible with: **Python 2.7-3.6**.

You can also email me at Ehsan Haghighat.

## Getting started: 30 seconds to SciANN

The core data structure of SciANN is a `Functional`

, a way to organize inputs (`Variables`

) and outputs (`Fields`

) of a network.

Targets are imposed on `Functional`

instances using `Constraint`

s.

The SciANN model (`SciModel`

) is formed from inputs (`Variables`

) and targets(`Constraints`

). The model is then trained by calling the `solve`

function.

Here is the simplest `SciANN`

model:

```
from sciann import Variable, Functional, SciModel
from sciann.constraints import Data
x = Variable('x')
y = Functional('y')
# y_true is a Numpy array of (N,1) -- with N as number of samples.
model = SciModel(x, Data(y))
```

This is associated to the simplest neural network possible, i.e. a linear relation between the input variable `x`

and the output variable `y`

with only two parameters to be learned.

Plotting a network is as easy as passing a file_name to the SciModel:

```
model = SciModel(x, Data(y), plot_to_file='file_path')
```

Once your model looks good, perform the learning with `.solve()`

:

```
# x_true is a Numpy array of (N,1) -- with N as number of samples.
model.train(x_true, y_true, epochs=5, batch_size=32)
```

You can iterate on your training data in batches and in multiple epochs. Please check Keras documentation on `model.fit`

for more information on possible options.

You can evaluate the model any time on new data:

```
classes = model.predict(x_test, batch_size=128)
```

In the application folder of the repository, you will find some examples of Linear Elasticity, Flow, Flow in Porous Media, etc.

## Installation

Before installing SciANN, you need to install the TensorFlow and Keras.

You may also consider installing the following **optional dependencies**:

- cuDNN (recommended if you plan on running Keras on GPU).
- HDF5 and h5py (required if you plan on saving Keras/SciANN models to disk).
- graphviz and pydot (used by visualization utilities to plot model graphs).

Then, you can install SciANN itself. There are two ways to install SciANN:

**Install SciANN from PyPI (recommended):**

Note: These installation steps assume that you are on a Linux or Mac environment.
If you are on Windows, you will need to remove `sudo`

to run the commands below.

```
sudo pip install sciann
```

If you are using a virtualenv, you may want to avoid using sudo:

```
pip install sciann
```

**Alternatively: install SciANN from the GitHub source:**

First, clone SciANN using `git`

:

```
git clone https://github.com/sciann/sciann.git
```

Then, `cd`

to the SciANN folder and run the install command:

```
sudo python setup.py install
```

or

```
sudo pip install .
```

## Why this name, SciANN?

Scientific Computational with Artificial Neural Networks.

Scientific computations include solving ODEs, PDEs, Integration, Differentiation, Curve Fitting, etc.