Obtaining PSI4¶

How to obtain Psi4: start with find-the-code quiz, end in `{top-level-psi4-dir}`¶

A better decision tree is available at psicode.org/installs/latest, though the below remains valid.

Take a quiz to find the best version of the codebase for your needs, be it binary, tarball, or version-controlled repository. Or, select outright among:

Binary Installer
Conda Binary Package
Clone from GitHub Repository
Fork from GitHub Repository (only path to develop PSI4)
Tarball from GitHub Repository

Find-the-code Quiz¶

A better decision tree is available at psicode.org/installs/latest, though the below remains valid.

I just want to run the code. I may tweak the Python, but I’m not developing anything to contribute back to the code base.
- Provided I still get good, threaded BLAS/LAPACK, OpenMP parallelism, and optimization for a variety of processor architectures, I’m willing to forgo architecture tuning wizardry to avoid compiling it myself.
  - I’m on Linux or Mac or Windows with Ubuntu Bash Shell.
    - I’m familiar with conda and want to manage PSI4 as an ordinary conda package. — Goto Binary-Package
    - I just want a PSI4 installer. — Goto Binary-Installer
- I want to compile it myself to eke out best performance on my computer. I accept responsibility for navigating compiler, threading, and BLAS/LAPACK compatibility
  - I’m willing to have minimal dealings with git (e.g., commands git clone and git pull) in return for easy access in future to new features and bug fixes. — Goto Clone-from-GitHub
  - I don’t want to deal with this newfangled git, just give me a tarball of the source code — Goto Tarball-from-GitHub
I want to run and develop in PSI4.
- In keeping with the open-source philosophy, I don’t mind my code being as public as Psi4 itself during the development process. — Goto Fork-from-GitHub
- I want to develop using PSI4 infrastructure and libraries, not on them; I think a plugin might do.
  - I’ve got a PSI4 compilation. Use it, then consult plugins
  - I’d rather not compile PSI4 or I don’t have compilers — Goto Binary-Package then consult plugins through conda
I really like parentheses and/or DBOC, so I want Psi3. — Psi3 is available from sourceforge, but you’re on your own.

Binary Installer¶

Get Initially

Just go to http://www.psicode.org/downloads.html, select “Installer”, “Stable Release”, and your choice of architecture and Python version, and follow the instructions there.
Build

Not applicable as binary is pre-built.
Get Updates directions
```
>>> conda update psi4
```
Contribute Back

Not applicable as not under git control.

Conda Binary Package¶

Get Initially

The pre-compiled conda packages at https://anaconda.org/psi4/psi4 can be installed into an existing Anaconda or Miniconda distribution according to directions. Locally, install into a conda environment as below.
```
>>> conda create -n p4env psi4 -c psi4
>>> conda activate p4env
```
```
>>> # nightly build
>>> conda create -n p4env psi4 -c psi4/label/dev
>>> # Windows
>>> conda create -n p4env psi4 -c psi4 -c conda-forge
```
Build

Not applicable as binary is pre-built.
Get Updates directions
```
>>> conda update psi4 -c psi4
```
Contribute Back

Not applicable as not under git control.

Clone from GitHub Repository¶

Get Initially

The PSI4 repository at https://github.com/psi4/psi4 works like every other GitHub repo. Locally, clone as below.
```
# use https or ssh
>>> git clone https://github.com/psi4/psi4.git
>>> cd psi4
# this is your {top-level-psi4-dir}
```
Build directions

Get Updates

# on branch master
>>> git pull origin master

Contribute Back

Contributions cannot be made directly to the main repository. Fork instead.

To convert clone to fork, go to https://github.com/psi4/psi4, and hit the Fork button to store a PSI4 repository in your GitHub account.
```
>>> git remote rename origin upstream
>>> git remote add origin https://github.com/johndoe/psi4.git
```

Fork from GitHub Repository¶

Get Initially

Go to https://github.com/psi4/psi4, and hit the Fork button to store a PSI4 repository in your GitHub account. Locally, proceed to clone:
```
# replace johndoe
# use https or ssh
>>> git clone https://github.com/johndoe/psi4.git
>>> cd psi4
# this is your {top-level-psi4-dir}
```
Set up a connection between your forked repository and the parent repository.
```
>>> git remote add upstream https://github.com/psi4/psi4.git
```
Build directions
Get Updates

Locally, update your fork from the parent repository and store on GitHub at your fork.
```
# on branch working_branch
>>> git pull --rebase upstream master
>>> git push origin working_branch
```
Remember: Working in the master branch of a fork is considered bad practice.
Contribute Back

PSI4 contributions process here and here. Consider preparing your contribution in a branch then issue a GitHub pull request.

Tarball from GitHub Repository¶

Get Initially

Discouraged! From the PSI4 repository at https://github.com/psi4/psi4, hit the “Clone or download” then “Download ZIP” button. Locally, unpack as below.
```
>>> unzip psi4-master.zip
>>> cd psi4-master
# this is your {top-level-psi4-dir}
```
Build directions
Get Updates

Download new tarball and rebuild.
Contribute Back

Not applicable as source not under git control.

What is the suggested GitHub workflow¶