Versions Compared

Old Version 32

changes.mady.by.user Unknown User (nagc)

Saved on

compared with

New Version 33

changes.mady.by.user Unknown User (nagc)

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Code Block
titlegcc/gfortran compilers
cd grib_api_1.9.18
CC=gcc FC=gfortran  \
CCFLAGS="-g -O2 -m64 -march=native" FCFLAGS="-g -O2 -m64 -march=native"  \
 ./configure --prefix=../grib_api_gcc --enable-pthread --disable-jpeg --disable-omp-packing --disable-vector

Note the use of the backslash '\' to allow the command to use two lines.

...

disablevectorLikewise, on vector computer hardware (e.g. NEC), you can this option and grib_api will use a more efficient packing/unpacking method suitable for vector machines.
--prefix=../grib_api_gccThis specifies where you want the grib_api files to be installed. In our example here, the source code is in $HOME/ecmwf/grib_api_1.9.18 and we will put the compiled grib_api libraries in our example directory $HOME/ecmwf/grib_api_gcc. You are free to choose any installation directory but it's recommended to keep the installed binaries & libraries in a separate directory to the source code in case different compiler versions are needed. On a shared high performance computer facility, the install path would most likely be somewhere central. If nothing is specified for --prefix, by default grib_api will install in /usr/local.
--disable-jpegOpenIFS does not need to support JPEG and PNG for data compression. This removes the need to link OpenIFS against the Jasper library (libjasper.a).
--disable-omp-packingOpenMP enabled packing is removed as the model needs to have control over OpenMP multithreading. This is usually disabled by default but it's best to enforce it in case the default changes for future releases.-
--enable--enable-pthreadThis option ensures that grib_api is thread-safe. Again, this is normally the default but we enforce it here as OpenIFS will call grib_api from parallel threads.
Info
titleOther options

The --help option to configure can be used to see what other options are possible, also see the grib_api website for more detailed documentation.

The --enable-python option enables the python interface and is optional but might be useful if you intend to use/write software to access the GRIB output files. If the make fails because of a missing numpy header file you should add the --disable-numpy option.

The --enable-vector option should be used on vector based computers (e.g. NEC). Grib_api will then use a more efficient packing/unpacking method suitable for vector hardware. n.b. there is a bug in the 1.9.18 release that if the --disable-vector option is used, this has the reverse effect of enabling the vector code. See grib_api issue GRIB-269 for more details.

Info
titleShared and static libraries

grib_api will build both shared and static libraries by default. Shared libraries need to be built if the python interface is used.

Some compilers will link to the shared version by default if both are found (e.g. the GNU compiler). To ensure the correct version of grib_api is found (in case several are available on your system), OpenIFS explicitly lists the static library in the FCM configuration files. Alternately, if you prefer to use the shared library, you must ensure that your LD_LIBRARY_PATH variable is set so that 1.9.18 version compiled here is found first. Alternately, the option  --disable-shared stops the shared libraries from being generated, only the static libraries are built and will be linked. However, this may prevent other grib api tools working and is not generally recommended.

...