c960d292ec
A mindless task for a lazy weekend: convert all the README and README.txt files to Markdown. Paired with the slow conversion of all of our man pages to Markdown, this gives a uniform language to the Open MPI docs. This commit moved a bunch of copyright headers out of the top-level README.txt file, so I updated the relevant copyright header years in the top-level LICENSE file to match what was removed from README.txt. Additionally, this commit did (very) little to update the actual content of the README files. A very small number of updates were made for topics that I found blatently obvious while Markdown-izing the content, but in general, I did not update content during this commit. For example, there's still quite a bit of text about ORTE that was not meaningfully updated. Signed-off-by: Jeff Squyres <jsquyres@cisco.com> Co-authored-by: Josh Hursey <jhursey@us.ibm.com>
36 строки
1.4 KiB
Markdown
36 строки
1.4 KiB
Markdown
# Open MPI extension: shortfloat
|
|
|
|
Copyright (c) 2018 FUJITSU LIMITED. All rights reserved.
|
|
|
|
This extension provides additional MPI datatypes `MPIX_SHORT_FLOAT`,
|
|
`MPIX_C_SHORT_FLOAT_COMPLEX`, and `MPIX_CXX_SHORT_FLOAT_COMPLEX`,
|
|
which are proposed with the `MPI_` prefix in June 2017 for proposal in
|
|
the MPI 4.0 standard. As of February 2019, it is not accepted yet.
|
|
|
|
See https://github.com/mpi-forum/mpi-issues/issues/65 for moe details
|
|
|
|
Each MPI datatype corresponds to the C/C++ type `short float`, the C
|
|
type `short float _Complex`, and the C++ type `std::complex<short
|
|
float>`, respectively.
|
|
|
|
In addition, this extension provides a datatype `MPIX_C_FLOAT16` for
|
|
the C type `_Float16`, which is defined in ISO/IEC JTC 1/SC 22/WG 14
|
|
N1945 (ISO/IEC TS 18661-3:2015). This name and meaning are same as
|
|
that of MPICH. See https://github.com/pmodels/mpich/pull/3455.
|
|
|
|
This extension is enabled only if the C compiler supports `short float`
|
|
or `_Float16`, or the `--enable-alt-short-float=TYPE` option is passed
|
|
to the Open MPI `configure` script.
|
|
|
|
NOTE: The Clang 6.0.x and 7.0.x compilers support the `_Float16` type
|
|
(via software emulation), but require an additional linker flag to
|
|
function properly. If you wish to enable Clang 6.0.x or 7.0.x's
|
|
software emulation of `_Float16`, use the following CLI options to Open
|
|
MPI configure script:
|
|
|
|
```
|
|
./configure \
|
|
LDFLAGS=--rtlib=compiler-rt \
|
|
--with-wrapper-ldflags=--rtlib=compiler-rt ...
|
|
```
|