Installing Chemist

Chemist uses CMaize as its build system, more detailed build instructions can be found here.

Note

We strongly recommend users use CMake toolchains to pass arguments to the cmake command. Typically CMake toolchains live in files named <prefix>-toolchain.cmake, where <prefix>- is an optional prefix to distinguish among toolchains. The contents of the CMake toolchain file usually just sets configuration values set via the standard CMake set function, i.e., set(<option_name> <value>).

Install Command

In many cases Chemist can be installed by:

git clone https://github.com/NWChemEx/Chemist
cd Chemist
cmake -H. -Bbuild -DCMAKE_TOOLCHAIN_FILE=<path/to/toolchain/file> \
                  -DCMAKE_INSTALL_PREFIX=<where/to/install/Chemist>
cmake --build build --target install

Where <path/to/toolchain/file> should be replaced by the path to your toolchain file, and <where/to/install/Chemist> should be replaced with where you want to put the installed library (absolute path is recommended in both cases).

Note

The above command will build serially. To build Chemist with N processors additionally pass --parallel <N> to the last command in the above code block, i.e.,

cmake --build build --parallel <N> --target install

Configuration Options

This is a list of configuration options recognized by Chemist’s build system.

BUILD_TESTING.

Off by default. Set to a truth-y value to enable testing.

BUILD_DOCS.

Off by default. Set to a truth-y value to build the C++ API documentation. This variable is defined by the nwx_cxx_api_docs CMake module.

ONLY_BUILD_DOCS.

Off by default. If BUILD_DOCS is set to a truth-y value and ONLY_BUILD_DOCS is also set to a truth-y value, then the configure process will skip all other aspects of the configuration aside from creating the chemist_cxx_api target. This variable is defined by the nwx_cxx_api_docs CMake module.

BUILD_PYBIND11_PYBINDINGS.

On by default. When enabled the optional Python API is built.

ENABLE_EXPERIMENTAL_FEATURES.

Off by default. When set to a truth-y value classes and functions which are in a pre-release state will be built.

Chemist Dependencies

If you have a problem building Chemist it’s most likely because you don’t have a new enough version of CMake installed or because CMake can’t find one of Chemist’s dependencies. This section enumerates Chemist’s dependencies.

Required Dependencies

These are dependencies which must be pre-installed and can not be built by Chemist’s build system.

Boost

Chemist needs access to Boost’s header-only container library. If you do a lot of C++ development you’ve likely already installed Boost. Otherwise check your OS’s package manager.

C++ Compiler

Chemist relies on the C++17 standard and should work with any C++17 compliant compiler (GCC 9.x or newer). C++ compilers can often be installed by your OS’s package manager. CMake detects your C++ compiler via the value of CMAKE_CXX_COMPILER. So ensure CMAKE_CXX_COMPILER is set to the C++ compiler you want to use.

MPI

Chemist’s heaviest dependency is ParallelZone which implicitly brings in MPI (the message passing interface). Users must have an MPI distribution installed prior to building ParallelZone. MPI distributions exist in most major OS-level package managers, so check your package manager before installing MPI from source.While CMake can find MPI if it is installed in your OS’s standard spot, you may need to give CMake a hint in some cases. MPI provides compiler wrappers and it’s best to let CMake discover MPI via the C++ wrapper. Add:

set(MPI_CXX_COMPILER <path/to/mpicxx>)

to your toolchain to point CMake to MPI’s C++ compiler wrapper.

Optional Dependencies

These are dependencies that Chemist’s build system can not build; however, they are only required if certain features are enabled.

Doxygen

Home Page

Used to generate the C++ API documentation. Only needed if BUILD_DOCS is set to a truth-y value.

Python

Needed if BUILD_PYBIND11_PYTHONBINDINGS is enabled. You will need the developer headers and libraries for Python.

Other Dependencies

The dependencies in this section can be built by Chemist’s build system when they are not located. Under normal circumstances users can ignore them. They are listed here primarily for completeness.

Catch2

URL: https://github.com/catchorg/Catch2

Used for unit testing. Only needed if unit testing is enabled (controlled by the CMake variable BUILD_TESTING, which is OFF by default).

CMaize

URL: https://cmakepp.github.io/CMaize/index.html

Used to simplify writing a CMake-based build system. The build system will grab it for you.

ParallelZone

URL: <https://www.github.com/>

Parallel runtime system built and maintained by the NWChemEx team. As a slight caveat, Chemist’s build system can only automatically build ParallelZone if MPI is installed and visible to CMake.

TensorWrapper

URL: https://github.com/NWChemEx/TensorWrapper

Provides a unified API to a number of tensor libraries. TensorWrapper is currently under heavy development and not considered stable. It is only needed when ENABLE_EXPERIMENTAL_FEATURES is set to a truth-y value.

utilities

URL: https://www.github.com/NWChemEx/utilities

Utility classes used throughout the NWChemEx stack.