Testing Nalu

Nalu’s regression tests and unit tests are run nightly using the GCC and Intel compilers against the Trilinos master and development branches on a machine at NREL. The results can be seen at the CDash Nalu website.

Running Tests Locally

The nightly tests are implemented using CTest and these same tests are available to developers to run locally as well. Due to the nature of error propagation of calculations in computers, results of regression testing can be difficult to keep consistent. Output from Nalu can vary from established reference data for the regression tests based on the compiler you are using, the types of optimizations set, and the versions of the third-party libraries Nalu utilizes, along with the blas/lapack implementation in use. Therefore it may make sense when you checkout Nalu to create your own reference data for the tests for the machine and configuration you are using, which is described later in this document. Or you can use a lower tolerance when running the tests. At the moment, a single tolerance is chosen in which to use for all the tests. The following instructions will describe how to run Nalu’s tests.

Since Nalu’s tests require a large amount of data (meshes), this data is hosted in a separate repository from Nalu. This mesh repo is set as a submodule in the reg_tests/mesh directory in the main Nalu repository. Submodule repos are not checked out by default, so either use git submodule init and then git submodule update to clone it in your checkout of Nalu, or when you first clone Nalu you can also use git clone --recursive <repo_url> to checkout all submodules as well.

Once this submodule is intialized and cloned, you will need to configure Nalu with testing on. To configure Nalu with testing enabled, in Nalu’s existing build directory, we will run this command:

cmake -DTrilinos_DIR:PATH=`spack location -i nalu-trilinos` \
      -DYAML_DIR:PATH=`spack location -i yaml-cpp` \

Note we have chosen to originally build Nalu with Spack in this case, hence the use of spack location -i <package> to locate our Yaml and Trilinos installations. Then we use -DENABLE_TESTS:BOOL=ON to enable CTest. Once Nalu is configured, you should be able to run the tests by building Nalu in the build directory, and running make test or ctest. Looking at ctest -h will show you many ways you can run tests and choose which tests to run.

There are advantages to using CTest, such as being able to run subsets of the tests, or tests matching a particular regular expression for example. To do so, in the build directory, you can run ctest -R femHC to run the test matching the femHC regular expression. Other useful capabilities are ctest --output-on-failure to see test outputs when they fail, ctest --rerun-failed to only run the tests that previously failed, ctest --print-labels to see the test labels, and ctest -L unit to run the tests with label ‘unit’ for example. All testing related log files and output can be seen in Nalu/build/Testing/Temporary and Nalu/build/reg_tests after the test have been run.

To define your own tolerance for tests, at configure time, add -DTEST_TOLERANCE=0.0001 for example to the Nalu CMake configure line.

Updating Reference Data for Your Machine

When running the tests, the norms for each test are the output and they are ‘diffed’ against the ‘gold’ norms that we have established for each test. To dictate whether or not a test passes, we use a chosen tolerance in which we allow the results to deviate from the ‘gold’ norm. As stated earlier, these ‘gold’ norms are not able to reflect every configuration of Nalu, per compiler, optimization, TPL versions, blas/lapack version, etc. This tolerance is currently defined in the CMakeLists.txt in Nalu’s reg_tests directory. This tolerance can also be passed into Nalu at configure time using -DTEST_TOLERANCE=0.0000001 for example. To update the ‘gold’ norms locally to your configuration, merely run the tests once, and copy the *.norm files in the build/reg_tests/test_files directory to the corresponding test location in reg_tests/test_files while overwriting the current ‘gold’ norms.

In regards to ‘official’ gold norms, Linux gcc is currently used. For the current list of TPLs, refer to the current list.

Adding Tests to Nalu

The testing infrastructure is almost completely confined to the reg_tests directory. To add a test to Nalu, we need to add the test name, and create a test directory to place the input files and gold norms for the test. First, the test itself can be added to the list of CTest tests by adding a line to the CTestList.cmake file. For a single regression test, provided it is similar to the categories shown at the top of the CTestList.cmake file, it can likely be added with a single line using the test name and amount of processes you would like to run the test with and choosing the correct function to use. For example:

add_test_r(mytest 6)

After this has been done, in the reg_tests/test_files directory, you should add a directory corresponding to your test name and include the input file, mytest.i, and reference output file mytest.norm.gold. If you are using an xml file that doesn’t exist in the xml directory, you will need to commit that as well.

To see commands used when running the tests, see the functions at the top of the CTestList.cmake file. These functions ultimately create CTestTestFile.cmake files in the CMake build directory at configure time. You can see the exact commands used for each test after configure in the build/reg_tests/CTestTestFile.cmake file.

Note if your test doesn’t conform to an existing archetype, a new function in CTestList.cmake may need to be created. Also, if you are using a mesh file that doesn’t exist in the mesh repo, you will need to add it, and update the submodule in the Nalu main repo to use the latest commit of the mesh submodule repo.

Adding Testing Machines to CDash

To add a testing machine that will post results to CDash first means that you should have all software dependencies satisified for Nalu. Next the script located at CTestNightlyScript.cmake can be run for example as:

ctest \
  -DHOST_NAME=machine.domain.com \
  -DEXTRA_BUILD_NAME=Linux-gcc-whatever \
  -VV -S ${NALU_DIR}/reg_tests/CTestNightlyScript.cmake

In this case ${NALU_TESTING_DIR} is one directory above where the Nalu repo has been checked out. This runs CTest in scripting mode with verbosity on and it will update the Nalu repo with the latest revisions, configure, build, test, and finally submit results to the CDash site. Since CTest does the building, it needs to know the locations of Yaml and Trilinos. For examples of nightly testing, refer to the testing scripts currently being run here.