don't set CMAKE_TUNE_FLAGS to anything by default

This commit is contained in:
Axel Kohlmeyer
2020-07-15 16:19:48 -04:00
parent bf37e6aae1
commit 73a076daf3
3 changed files with 14 additions and 23 deletions

View File

@ -193,14 +193,17 @@ compiler and any :doc:`accelerator packages <Speed_packages>` you have
included in the build.
You can tell CMake to look for a specific compiler with setting CMake
variable during configuration. For a few common choices, there are also
presets in the ``cmake/presets`` folder. For convenience, there is a
``CMAKE_TUNE_FLAGS`` variable that can be set to apply global compiler
options. More on that below, but you can also specify the corresponding
``CMAKE_*_FLAGS`` variables individually if you want to experiment with
alternate optimization flags. You should specify all 3 compilers, so
that the (few) LAMMPS source files written in C or Fortran are built
with a compiler consistent with the one used for the C++ files:
variables (listed below) during configuration. For a few common
choices, there are also presets in the ``cmake/presets`` folder. For
convenience, there is a ``CMAKE_TUNE_FLAGS`` variable that can be set to
apply global compiler options (applied to compilation only), to be used
for adding compiler or host specific optimization flags in addition to
the "flags" variables listed below. You may also specify the
corresponding ``CMAKE_*_FLAGS`` variables individually, if you want to
experiment with alternate optimization flags. You should specify all 3
compilers, so that the (few) LAMMPS source files written in C or Fortran
are built with a compiler consistent with the one used for the C++
files:
.. code-block:: bash
@ -229,11 +232,7 @@ can be loaded with `-C ../cmake/presets/clang.cmake`. Similarly,
In addition you can set ``CMAKE_TUNE_FLAGS`` to specifically add
compiler flags to tune for optimal performance on given hosts. By
default these are initialized to some compiler specific flags, to
optimize the LAMMPS executable with optimizations and instructions
available on the host where LAMMPS is compiled. For example, for Intel
compilers this would be ``-xHost`` and for GNU compilers this would be
``-march=native``. To turn these flags off, do ``-D CMAKE_TUNE_FLAGS=``.
default this variable is empty.
.. note::