Compilation and Installation

Use PuTTY to log in to the server as the root user.
Run the following commands to decompress the WRF installation package.
```
cd /path/to/WRF
tar -xvf WRF-3.8.1.tar.gz
```
Run the following command to switch to WRF source code directory:
```
cd WRF-3.8.1
```

Run the following command to modify the arch/configure_new.defaults file.

Open the arch/configure_new.defaults file.
```
vim arch/configure_new.defaults
```

Press i to enter the insert mode and add the following content above 1856:

################################################## #########
#ARCH   Linux   aarch64,gnu OpenMPI #serial smpar dmpar dm+sm
DESCRIPTION     =       GNU ($SFC/$SCC)
DMPARALLEL      =        1
OMPCPP          =        -D_OPENMP
OMP             =        -fopenmp
OMPCC           =        -fopenmp
SFC             =       gfortran
SCC             =       gcc
CCOMP           =       gcc
DM_FC           =       mpif90 -f90=$(SFC)
DM_CC           =       mpicc -cc=$(SCC) -DMPI2_SUPPORT
FC              =       CONFIGURE_FC
CC              =       CONFIGURE_CC
LD              =       $(FC)
RWORDSIZE       =       CONFIGURE_RWORDSIZE
PROMOTION       =       #-fdefault-real-8
ARCH_LOCAL      =       -DNONSTANDARD_SYSTEM_SUBR  -DWRF_USE_CLM
CFLAGS_LOCAL    =       -w -O3 -c -march=armv8.2-a -L/path/to/MATH/lib -lmathlib
LDFLAGS_LOCAL   =
CPLUSPLUSLIB    =
ESMF_LDFLAG     =      $(CPLUSPLUSLIB)
FCOPTIM         =       -O3 -ftree-vectorize -funroll-loops -march=armv8.2-a -L/path/to/MATH/lib -lmathlib
FCREDUCEDOPT    =       $(FCOPTIM)
FCNOOPT         =       -O0
FCDEBUG         =       # -g $(FCNOOPT)  # -fbacktrace -ggdb-fcheck=bounds,do,mem,pointer -ffpe-trap=invalid,zero,overflow
FORMAT_FIXED    =       -ffixed-form
FORMAT_FREE     =       -ffree-form -ffree-line-length-none
FCSUFFIX        =
BYTESWAPIO      =       -fconvert=big-endian -frecord-marker=4
FCBASEOPTS_NO_G =       -w $(FORMAT_FREE) $(BYTESWAPIO)
FCBASEOPTS      =       $(FCBASEOPTS_NO_G) $(FCDEBUG)
MODULE_SRCH_FLAG =
TRADFLAG        =      -traditional
CPP             =      /lib/cpp -P
AR              =      ar
ARFLAGS         =      ru
M4              =      m4 -G
RANLIB          =      ranlib
RLFLAGS         =
CC_TOOLS        =      $(SCC)

Press Esc, type :wq!, and press Enter to save the file and exit.

Run the following commands to configure the pre-compilation environment:

export WRFIO_NCD_LARGE_FILE_SUPPORT=1
export NETCDF=/path/to/NETCDF
export HDF5=/path/to/HDF5
export PNETCDF=/path/to/PNETCDF
export CPPFLAGS="-I$HDF5/include -I$PNETCDF/include -I$NETCDF/include"
export LDFLAGS="-L$HDF5/lib -L$PNETCDF/lib -L$NETCDF/lib -lnetcdf -lnetcdff -lpnetcdf -lhdf5_hl -lhdf5 -lz"

Run the following command to generate a configuration file:
```
echo 4 | ./configure
```
Run the following command to modify the ./phys/module_cu_g3.F file:
1. Open the ./phys/module_cu_g3.F file.
```
vim ./phys/module_cu_g3.F
```
2. Press i to enter the insert mode and modify the content in line 3125.
```
integer,  dimension (33) :: seed
```
3. Press Esc, type :wq!, and press Enter to save the file and exit.
You can skip this step during the installation of WRF 4.1.2.
Run the following commands to load the compiler and set the Open MPI environment variables.
```
export PATH=/path/to/GNU/bin:/path/to/OPENMPI/bin:$PATH
export LD_LIBRARY_PATH=/path/to/GNU/lib64:/path/to/OPENMPI/lib:$LD_LIBRARY_PATH
```
If the environment variables of the compiler and Open MPI have been declared, skip this step.
Run the following command to perform compilation and installation:
```
./compile -j 16 em_real 2>&1 | tee -a compile.log
```
Run the following command to verify the installation:
```
ls main
```
If the following information is displayed (the wrf.exe file is generated), the installation is successful. The installation of the main program takes approximately 10 minutes.

Parent topic: WRF 3.8.1 Porting Guide (CentOS 7.6)