Contributing to ABACUS

First of all, thank you for taking time to make contributions to ABACUS! This file provides the more technical guidelines on how to realize it. For more non-technical aspects, please refer to the ABACUS Contribution Guide

Table of Contents

Got a question?

Please referring to our GitHub issue tracker, and our developers are willing to help. If you find a bug, you can help us by submitting an issue to our GitHub Repository. Even better, you can submit a Pull Request with a patch. You can request a new feature by submitting an issue to our GitHub Repository. If you would like to implement a new feature, please submit an issue with a proposal for your work first, and that ensures your work collaborates with our development road map well. For a major feature, first open an issue and outline your proposal so that it can be discussed. This will also allow us to better coordinate our efforts, prevent duplication of work, and help you to craft the change so that it is successfully accepted into the project.

Structure of the package

Please refer to our instructions on how to installing ABACUS. The source code of ABACUS is based on several modules. Under the ABACUS root directory, there are the following folders:

  • cmake: relevant files for finding required packages when compiling the code with cmake;

  • docs: documents and supplementary info about ABACUS;

  • examples: some examples showing the usage of ABACUS;

  • source: the source code in separated modules, under which a test folder for its unit tests;

  • tests: End-to-end test cases;

  • tools: the script for generating the numerical atomic orbitals.

For those who are interested in the source code, the following figure shows the structure of the source code.

|-- module_base                 A basic module including
|   |                           (1) Mathematical library interface functions: BLAS, LAPACK, Scalapack;
|   |                           (2) Custom data classes: matrix, vector definitions and related functions;
|   |                           (3) Parallelization functions: MPI, OpenMP;
|   |                           (4) Utility functions: timer, random number generator, etc.
|   |                           (5) Global parameters: input parameters, element names, mathematical and physical constants.
|   |-- module_container        The container module for storing data and performing operations on them and on different architectures.
|-- module_basis                Basis means the basis set to expand the wave function.
|   |-- module_ao               Atomic orbital basis set to be refactored.
|   |-- module_nao              New numerical atomic orbital basis set for two-center integrals in LCAO calculations
|   `-- module_pw               Data structures and relevant methods for planewave involved calculations
|-- module_cell                 The module for defining the unit cell and its operations, and reading pseudopotentials.
|   |-- module_neighbor         The module for finding the neighbors of each atom in the unit cell.
|   |-- module_paw              The module for performing PAW calculations.
|   |-- module_symmetry         The module for finding the symmetry operations of the unit cell.
|-- module_elecstate            The module for defining the electronic state and its operations.
|   |-- module_charge           The module for calculating the charge density, charge mixing
|   |-- potentials              The module for calculating the potentials, including Hartree, exchange-correlation, local pseudopotential, etc.
|-- module_esolver              The module defining task-specific driver of corresponding workflow for evaluating energies, forces, etc., including lj, dp, ks, sdft, ofdft, etc.
|   |                           TDDFT, Orbital-free DFT, etc.
|-- module_hamilt_general       The module for defining general Hamiltonian that can be used both in PW and LCAO calculations.
|   |-- module_ewald            The module for calculating the Ewald summation.
|   |-- module_surchem          The module for calculating the surface charge correction.
|   |-- module_vdw              The module for calculating the van der Waals correction.
|   |-- module_xc               The module for calculating the exchange-correlation energy and potential.
|-- module_hamilt_lcao          The module for defining the Hamiltonian in LCAO calculations.
|   |-- hamilt_lcaodft          The module for defining the Hamiltonian in LCAO-DFT calculations.
|   |   |-- operator_lcao       The module for defining the operators in LCAO-DFT calculations.
|   |-- module_deepks           The module for defining the Hamiltonian in DeepKS calculations.
|   |-- module_dftu             The module for defining the Hamiltonian in DFT+U calculations.
|   |-- module_gint             The module for performing grid integral in LCAO calculations.
|   |-- module_hcontainer       The module for storing the Hamiltonian matrix in LCAO calculations.
|   `-- module_tddft            The module for defining the Hamiltonian in TDDFT calculations.
|-- module_hamilt_pw            The module for defining the Hamiltonian in PW calculations.
|   |-- hamilt_ofdft            The module for defining the Hamiltonian in OFDFT calculations.
|   |-- hamilt_pwdft            The module for defining the Hamiltonian in PW-DFT calculations.
|   |   |-- operator_pw         The module for defining the operators in PW-DFT calculations.
|   `-- hamilt_stodft           The module for defining the Hamiltonian in STODFT calculations.
|-- module_hsolver              The module for solving the Hamiltonian with different diagonalization methods, including CG, Davidson in PW
|   |                           calculations, and scalapack and genelpa in LCAO calculations.
|-- module_io                   The module for reading of INPUT files and output properties including band structure, density of states, charge density, etc.
|-- module_md                   The module for performing molecular dynamics.
|-- module_psi                  The module for defining the wave function and its operations.
|-- module_relax                The module for performing structural optimization.
|   |-- relax_new               The module for performing structural optimization with new algorithm, optimized for cell and ion simultaneously.
|   `-- relax_old               The module for performing structural optimization with old algorithm, optimized for cell and ion separately.
|-- module_ri                   The module for performing RI calculations.

Submitting an Issue

Before you submit an issue, please search the issue tracker, and maybe your problem has been discussed and fixed. You can submit new issues by filling our issue forms. To help us reproduce and confirm a bug, please provide a test case and building environment in your issue.

Comment style for documentation

ABACUS uses Doxygen to generate docs directly from .h and .cpp code files.

For comments that need to be shown in documents, these formats should be used – Javadoc style (as follow) is recommended, though Qt style is also ok. See it in official manual.

A helpful VS Code extension – Doxygen Documentation Generator, can help you formating comments.

An practical example is class LCAO_Deepks, the effects can be seen on readthedocs page

  • Tips

    • Only comments in .h file will be visible in generated by Doxygen + Sphinx;

    • Private class members will not be documented;

    • Use Markdown features, such as using a empty new line for a new paragraph.

  • Detailed Comment Block

    /**
* ... text ...
*/

  • Brief + Detailed Comment Block

    /// Brief description which ends at this dot. Details follow
/// here.

/// Brief description.
/** Detailed description. */

  • Comments After the Item: Add a “<”

    int var; /**<Detailed description after the member */
int var; ///<Brief description after the member

  • Parameters usage: [in],[out],[in,out] description e.g.

    void foo(int v/**< [in] docs for input parameter v.*/);

    or use @param command.

  • Formula

    • inline: \f$myformula\f$

    • separate line: \f[myformula\f]

    • environment: \f{environment}{myformula}

    • e.g.

      \f{eqnarray*}{
        g &=& \frac{Gm_2}{r^2} \\
        &=& \frac{(6.673 \times 10^{-11}\,\mbox{m}^3\,\mbox{kg}^{-1}\,
            \mbox{s}^{-2})(5.9736 \times 10^{24}\,\mbox{kg})}{(6371.01\,\mbox{km})^2} \\
        &=& 9.82066032\,\mbox{m/s}^2
\f}

Code formatting style

We use clang-format as our code formatter. The .clang-format file in root directory describes the rules to conform with. For Visual Studio Code developers, the official extension of C/C++ provided by Microsoft can help you format your codes following the rules. With this extension installed, format your code with shift+command/alt+f. Configure your VS Code settings as "C_Cpp.clang_format_style": "file" (you can look up this option by pasting it into the search box of VS Code settings page), and all this stuff will take into effect. You may also set "editor.formatOnSave": true to avoid formatting files everytime manually.

Adding a unit test

We use GoogleTest as our test framework. Write your test under the corresponding module folder at abacus-develop/tests, then append the test to tests/CMakeLists.txt. If there are currently no unit tests provided for the module, do as follows. module_base provides a simple demonstration.

  • Add a folder named test under the module.

  • Append the content below to CMakeLists.txt of the module:

    IF (BUILD_TESTING)
  add_subdirectory(test)
endif()

  • Add a blank CMakeLists.txt under module*/test.

To add a unit test:

  • Write your test under GoogleTest framework.

  • Add your testing source code with suffix *_test.cpp in test directory.

  • Append the content below to CMakeLists.txt of the module:

    AddTest(
  TARGET <module_name>_<test_name> # this is the executable file name of the test
  SOURCES <test_name>.cpp

  # OPTIONAL: if this test requires external libraries, add them with "LIBS" statement.
  LIBS math_libs # `math_libs` includes all math libraries in ABACUS.
)

  • Build with -D BUILD_TESTING=1 flag, cmake will look for GoogleTest in the default path (usually /usr/local); if not found, you can specify the path with -D GTEST_DIR. You can find built testing programs under build/source/<module_name>/test.

  • Follow the installing procedure of CMake. The tests will move to build/test.

  • Considering -D BUILD_TESTING=1, the compilation will be slower compared with the case -D BUILD_TESTING=0.

Running unit tests

  1. Compiling ABACUS with unit tests.

    In order to run unit tests, ABACUS needs to be configured with -D BUILD_TESTING=ON flag. For example:

    cmake -B build -DBUILD_TESTING=ON

    then build ABACUS and unit testing with

    cmake --build build -j${number of processors}

    It is import to run the folloing command before running unit tests:

    cmake --install build

    to install mandatory supporting input files for unit tests. If you modified the unit tests to add new tests or learn how to write unit tests, it is convenient to run

    cmake --build build -j${number of processors} --target ${unit test name}

    to build a specific unit test. And please remember to run cmake --install build after building the unit test if the unit test requires supporting input files.

  2. Running unit tests

    The test cases are located in build/source/${module_name}/test directory. Note that there are other directory names for unit tests, for example, test_parallel for running parallel unit tests, test_pw for running unit tests only used in plane wave basis calculation.

    You can run a single test in the specific directory. For example, run

    ./cell_unitcell_test

    under the directory of build/source/module_cell/test to run the test cell_unitcell_test. However, it is more convenient to run unit tests with ctest command under the build directory. You can check all unit tests by

    ctest -N

    The results will be shown as

    Test project /root/abacus/build
Test   #1: integrated_test
Test   #2: Container_UTs
Test   #3: base_blas_connector
Test   #4: base_blacs_connector
Test   #5: base_timer
...

    Note that the first one is integrated test, which is not a unit test. It is the test suite for testing the whole ABACUS package. The examples are located in the tests/integrate directory.

    To run a subset of tests, run the following command

    ctest -R <test-match-pattern> -V

    For example, ctest -R cell will perform tests with name matched by cell. You can also run a single test with

    ctest -R <test-name>

    For example, ctest -R cell_unitcell_test_readpp will perform test cell_unitcell_test_readpp. To run all the unit tests, together with the integrated test, run

    cmake --build build --target test ARGS="-V --timeout 21600"

    in the abacus-develop directory.

Debugging the codes

For the unexpected results when developing ABACUS, GDB will come in handy.

  1. Compile ABACUS with debug mode.

    cmake -B build -DCMAKE_BUILD_TYPE=Debug

  2. After building and installing the executable, enter the input directory, and launch the debug session with gdb abacus. For debugging in Visual Studio Code, please set cwd to the input directory, and program to the path of ABACUS executable.

  3. Set breakpoints, and run ABACUS by typing “run” in GDB command line interface. If the program hits the breakpoints or exception is throwed, GDB will stop at the erroneous code line. Type “where” to show the stack backtrace, and “print i” to get the value of variable i.

  4. For debugging ABACUS in multiprocessing situation, mpirun -n 1 gdb abacus : -n 3 abacus will attach GDB to the master process, and launch 3 other MPI processes.

For segmentation faults, ABACUS can be built with Address Sanitizer to locate the bugs.

cmake -B build -DENABLE_ASAN=1

Run ABACUS as usual, and it will automatically detect the buffer overflow problems and memory leaks. It is also possible to use GDB with binaries built by Address Sanitizer.

Valgrind is another option for performing dynamic analysis.

Adding a new building component

ABACUS uses CMake as its default building system. To add a new building component:

  1. Add an OPTION to toggle the component to the CMakeLists.txt file under root directory. For example:

    OPTION(ENABLE_NEW_COMPONENT "Enable new component" OFF)

  2. Add the new component. For example:

    IF (ENABLE_NEW_COMPONENT)
  add_subdirectory(module_my_new_feature) # if the feature is implemented in a subdirectory
  find_package(NewComponent REQUIRED) # if third-party libs are required
  target_link_libraries(${ABACUS_BIN_NAME} PRIVATE NewComponent) # if the component is linked
  include_directories(${NewComponent_INCLUDE_DIRS}) # if the component is included
endif()

  3. Add the required third-party libraries to Dockerfiles.

  4. After the changes above are merged, submit another PR to build and test the new component in the CI pipeline.

    • For integration test and unit test: add -DENABLE_NEW_COMPONENT=ON to the building step at .github/workflows/test.yml.

    • For building test: add -DENABLE_NEW_COMPONENT=ON as a new configuration at .github/workflows/build_test_cmake.yml.

Generating code coverage report

This feature requires using GCC compiler. We use gcov and lcov to generate code coverage report.

  1. Add -DENABLE_COVERAGE=ON for CMake configure command.

    cmake -B build -DBUILD_TESTING=ON -DENABLE_COVERAGE=ON

  2. Build, install ABACUS, and run test cases. Please note that since all optimizations are disabled to gather running status line by line, the performance is drastically decreased. Set a longer time out to ensure all tests are executed.

    cmake --build build --target test ARGS="-V --timeout 21600"

    If configuration fails unfortunately, you can find required files (including three *.cmake and llvm-cov-wrapper), and copy these four files into /abacus-develop/cmake. Alternatively, you can define the path with option -D CMAKE_CURRENT_SOURCE_DIR.

  3. Generate HTML report.

    cd build/
make lcov

Now you can copy build/lcov to your local device, and view build/lcov/html/all_targets/index.html.

We use Codecov to host and visualize our code coverage report. Analysis is scheduled after a new version releases; this action can also be manually triggered.

Submitting a Pull Request

  1. Fork the ABACUS repository. If you already had an existing fork, sync the fork to keep your modification up-to-date.

  2. Pull your forked repository, create a new git branch, and make your changes in it:

    git checkout -b my-fix-branch

  3. Coding your patch, including appropriate test cases and docs. To run a subset of unit test, use ctest -R <test-match-pattern> to perform tests with name matched by given pattern.

  4. After tests passed, commit your changes with a proper message.

  5. Push your branch to GitHub:

    git push origin my-fix-branch

  6. In GitHub, send a pull request (PR) with deepmodeling/abacus-develop:develop as the base repository. It is required to document your PR following our guidelines.

  7. After your pull request is merged, you can safely delete your branch and sync the changes from the main (upstream) repository:

  • Delete the remote branch on GitHub either through the GitHub web UI or your local shell as follows:

    git push origin --delete my-fix-branch

  • Check out the master branch:

    git checkout develop -f

  • Delete the local branch:

    git branch -D my-fix-branch

  • Update your master with the latest upstream version:

    git pull --ff upstream develop

Commit message guidelines

A well-formatted commit message leads a more readable history when we look through some changes, and helps us generate change log. We follow up The Conventional Commits specification for commit message format. This format is also required for PR title and message. The commit message should be structured as follows:

<type>[optional scope]: <description>

[optional body]

[optional footer(s)]

  • Header

    • type: The general intention of this commit

      • Feature: A new feature

      • Fix: A bug fix

      • Docs: Only documentation changes

      • Style: Changes that do not affect the meaning of the code

      • Refactor: A code change that neither fixes a bug nor adds a feature

      • Perf: A code change that improves performance

      • Test: Adding missing tests or correcting existing tests

      • Build: Changes that affect the build system or external dependencies

      • CI: Changes to our CI configuration files and scripts

      • Revert: Reverting commits

    • scope: optional, could be the module which this commit changes; for example, orbital

    • description: A short summary of the code changes: tell others what you did in one sentence.

  • Body: optional, providing detailed, additional, or contextual information about the code changes, e.g. the motivation of this commit, referenced materials, the coding implementation, and so on.

  • Footer: optional, reference GitHub issues or PRs that this commit closes or is related to. Use a keyword to close an issue, e.g. “Fix #753”.

Here is an example:

Fix(lcao): use correct scalapack interface.

`pzgemv_` and `pzgemm_` used `double*` for alpha and beta parameters but not `complex*` , this would cause error in GNU compiler.

Fix #753.