Migrating fro Autotools to CMake

Migtrating from Autotools to CMake

This document provides a comprehensive list of a autotools configuration options, and where appropriate, their cmake equivalents.

Options for Installation Rules

An installation prefix directory is specified with cmake using -DCMAKE_INSTALL_PREFIX=/my/install/path". If not specified, cmake will install to /usr/local by default, which requires ROOT privilege. Furthermore, the installation prefix can only be specified at configure time.

By default, Octopus has the installation structure:

octopus-install/
  bin/
  include/
  lib/
  share/

Fine control over naming conventions can be achieved with the commands defined in the table below, however, it should not be necessary to override the installation rules for the project, and these options are largely untested.

Optimisation Options

Enabling optimisation for specific vectorial instructions is not directly supported by Octopus cmake, however, general optimisation is defined for GCC and Intel compilers within src/CMakeLists.txt, in the form of -march=native and -xHost, respectively. When -DOCTOPUS_NATIVE=On, the compiler enables all supported instruction subsets of the local machine’s processor. This comes at the expense of portability.

Enabling External Library Support

If a user wishes to link Octopus to any package, particularly those that are not installed in the standard directories searched by cmake, they can pass the option -D<PACKAGE>_ROOT=DIR. Calls to find_package(<PACKAGE>) will search in prefixes specified by the <PACKAGE>_ROOT CMake variable. The exact package names are case-sensitive, according to what is passed to find_package in Octopus’s CMakeLists.txt.

Equivalently, the user can add the relevant search paths to the CMAKE_PREFIX_PATH, either as an environment variable or as a cmake option. For example:

  -DCMAKE_PREFIX_PATH="/opt/homebrew/Cellar/metis/5.1.0;/opt/homebrew/Cellar/fftw/3.3.10_1;/opt/homebrew/opt/openblas"

For find_package(PACKAGE MODULE), the corresponding Find<Package>.cmake typically defines cache entries for the include paths and libraries it finds, such that the user does not have to. However, you can always override those by passing -D on the command line, according to the general pattern:

<PACKAGE>_INCLUDE_DIR, <PACKAGE>_INCLUDEDIR or <PACKAGE>_INCLUDE_DIRS
<PACKAGE>_LIBRARY or <PACKAGE>_LIBRARIES

In general, this is not recommended as it should not be necessary.

REQUIRED packages are searched for by cmake and cause the configuration to fail if not found. On the contrary, all OPTIONAL packages are also searched for, but do not affect configuration if they are not found. To ignore a package detected by cmake, one can use the cmake option:

-DCMAKE_DISABLE_FIND_PACKAGE_<PKG>=On

Misc Options