Welcome to Use Xponge!

Introduction

Xponge is a lightweight and easy to customize python package to perform pre- and post-processing of molecular simulations.

What can Xponge do?

Xponge includes three major categories of functionality, namely, the simulation system construction, simulation data transformation and analysis, and automated workflows for complex simulations. Xponge is mainly designed for the molecular dynamics (MD) program SPONGE[1], but it can also output some general format files such as mol2 and PDB, so it may help the other molecular modelling programs too.

Installation

Xponge can be used on all operating systems (Windows/Linux/MacOS). Some functions (See here for the detailed list) to do the quantum chemistry calculations can not be used on Windows because pyscf is not available on Windows.

1. pip install

bash pip install Xponge

2. source setup

• 2.1 Download or clone the source from the gitee or github repository

  The gitee repository is here. The github repository is here.

  git clone http://gitee.com/gao_hyp_xyj_admin/xponge.git
  git clone http://github.com/xia-yijie/xponge.git
  

• 2.2 Open the directory where you download or clone the repository

• 2.3 (Optional) Configure the environment

  It is recommended to use conda to configure the environment. Two yml files named install_requirements.yml and extras_requirements.yml are provided in the repository.

  It is recommanded to use the file install_requirements.yml to configure the environment. The file will only install the basic dependent packages. If a ModuleNotFoundError is raised when you are using Xponge, then install the module. This allows you to avoid installing many modules that you will never use, and also makes Xponge more cross-platform compatible. Here are the commands to use install_requirements.yml.

  bash conda env create -f install_requirements.yml conda activate Xponge

  All the dependent packages are listed in the dependencies section. If you don't want to install the dependent packages one by one (which can be really annoying), the file extras_requirements.yml can help you with the environment configuration except the packages mindspore and mindsponge. The two packages should be installed according to your device (e.g. whether the backend is CPU, GPU or Huawei Ascend Processors) and can not be simply installed by conda. Here are the commands to use extras_requirements.yml.

  bash conda env create -f extras_requirements.yml conda activate Xponge

  It is worth noting that extras_requirements.yml can not be used on Windows because pyscf is not available on Windows.

• 2.4 Run the command

  bash python setup.py install

Installation check

There are some unit tests in Xponge. You can do the basic test to check whether the installation is successful like this:

bash Xponge test --do base -o test --verbose 1

Here, Xponge can be replaced to python -m Xponge, python3 -m Xponge and so on according to your settings of the environmental variables. Some files will be generated after the test is finished.

Quickstart

Here is a simple example.

```python import Xponge

Import the force field you need

import Xponge.forcefield.amber.ff14sb

Build the molecule like this

peptide = ACE + ALA + NME

or like this

peptide2 = NALA + ALA * 10 + CALA

or like this

peptide3 = Xponge.GetPeptideFrom_Sequence("AAAAA")

See the documentation for more usage!

Save them as your favorite format

Xponge.savepdb(peptide, "ala.pdb") Xponge.savemol2(peptide2, "ala12.mol2") Xponge.savespongeinput(peptide3, "ala5") ```

Then we can see ala12.mol2 in VMD:

Here is another simple example.

```python import Xponge import Xponge.forcefield.amber.tip3p

box = Xponge.BlockRegion(0, 0, 0, 60, 60, 60) region1 = Xponge.BlockRegion(0, 0, 20, 20, 20, 40) region2 = Xponge.BlockRegion(0, 0, 40, 20, 20, 60) region3 = Xponge.BlockRegion(0, 0, 0, 20, 20, 20) region4 = Xponge.SphereRegion(20, 10, 30, 10) region5 = Xponge.BlockRegion(20, 0, 20, 60, 60, 60) region2or3 = Xponge.UnionRegion(region2, region3) region4and5 = Xponge.IntersectRegion(region4, region5) t = Xponge.Lattice("bcc", basismolecule=CL, scale=4) t2 = Xponge.Lattice("fcc", basismolecule=K, scale=3) t3 = Xponge.Lattice("sc", basismolecule=NA, scale=3) mol = t.Create(box, region1) mol = t2.create(box, region2or3, mol) mol = t3.create(box, region4and5, mol) Xponge.SavePDB(mol, "out.pdb") ```

Then we can see out.pdb in VMD:

Detailed usage and API documentation

All can be seen here.

Contribution Guideline

If you want to contribute to the main codebase or report some issues, see here for the guides.

Dependencies

Xponge does not depend on other packages except numpy for its basic use.

However, there are some complicated functions that depend on some other packages. If you do not install the dependent package, you can not use the related functions.

Here is the list of all packages which may be uesd:

| package name | description | how to install | | ------------------| --------------------------------- | ------------------------------ | | XpongeLib | c/c++ compiled library for Xponge | pip install XpongeLib | | pyscf [2-4] | quantum chemistry | pip install pyscf | | geometric[5] | geometry optimization | pip install geometric | | rdkit[6] | cheminformatics | conda install -c rdkit rdkit | | MDAnalysis[7-8] | trajectory analysis | pip install MDAnalysis | | matplotlib | plot and visualization | pip install matplotlib | | mindspore[9] | AI framework for machine learning | See the official website| | mindsponge[1] | end-to-end differentiable MD | See the official website|

References

[0] Y. Xia, Y. Q. Gao, J. Open Source Softw. (2022) DOI:10.21105/joss.04467

[1] Y.-P. Huang, et al. Chinese J. Chem. (2022) DOI: 10.1002/cjoc.202100456

[2] Q. Sun, et al. J. Chem. Phys. (2020) DOI: 10.1063/5.0006074

[3] Q. Sun, et al. Wiley Interdiscip. Rev. Comput. Mol. Sci. (2018) DOI: 10.1002/wcms.1340

[4] Q. Sun, J. Comp. Chem. (2015) DOI: 10.1002/jcc.23981

[5] L.-P. Wang, C.C. Song, J. Chem. Phys. (2016) DOI: 10.1063/1.4952956

[6] RDKit: Open-source cheminformatics. https://www.rdkit.org

[7] R. J. Gowers, et al. Proceedings of the 15th Python in Science Conference (2016) DOI: 10.25080/majora-629e541a-00e

[8] N. Michaud-Agrawal, et al. J. Comput. Chem. (2011) DOI: 10.1002/jcc.21787

[9] MindSpore: An Open AI Framwork. https://www.mindspore.cn/