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Alternative compilers - simple example

GCC is the most supported compiler

The ITSR Applications Team have compiled the majority of applications available via modules on Apocrita using GCC. Whilst other compilers are available on Apocrita as outlined below, you will receive the best support from us should you choose to use GCC as well.

In all of the examples so far in this tutorial, we have used the GCC compiler. Using other compilers is also possible, but it requires a different workflow.

For the purposes of the examples below, we are going to try compile and run a very simple C++ MPI binary, first with our recommended GCC and Open MPI stack, and then using Intel and Intel MPI.

Comparative GCC and Open MPI example

For the purposes of comparison, a spack.yaml template for compiling and running this example using our recommended GCC and Open MPI setup can be found in the spack-config-templates repository inside the environment-templates sub-directory for the version of Spack you are using - called helloworld-gcc-ompi.yaml:

Contents of spack.yaml for Hello World GCC/Open MPI (click to expand) 
spack:
  compilers:
  - compiler:
      spec: gcc@=11.4.1
      paths:
        cc: /bin/gcc
        cxx: /bin/g++
        f77: /bin/gfortran
        fc: /bin/gfortran
      flags: {}
      operating_system: rocky9
      target: x86_64
      modules: []
      environment: {}
      extra_rpaths: []
  - compiler:
      spec: gcc@=12.2.0
      paths:
        cc: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-11.4.1/gcc/12.2.0-6frskzg/bin/gcc
        cxx: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-11.4.1/gcc/12.2.0-6frskzg/bin/g++
        f77: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-11.4.1/gcc/12.2.0-6frskzg/bin/gfortran
        fc: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-11.4.1/gcc/12.2.0-6frskzg/bin/gfortran
      flags: {}
      operating_system: rocky9
      target: x86_64
      modules: []
      environment: {}
      extra_rpaths: []
  concretizer:
    unify: true
  config:
    install_tree:
      root: /data/scratch/${USER}/spack/apps
      projections:
        ^mpi: '{architecture}/{compiler.name}-{compiler.version}/{name}/{version}-{^mpi.name}-{^mpi.version}-{hash:7}'
        all: '{architecture}/{compiler.name}-{compiler.version}/{name}/{version}-{hash:7}'
    license_dir: /data/scratch/${USER}/spack/licenses
    source_cache: /data/scratch/${USER}/spack/cache
  modules:
    prefix_inspections:
      ./share/aclocal:
      - ACLOCAL_PATH
      ./lib:
      - LD_LIBRARY_PATH
      - LIBRARY_PATH
      ./lib64:
      - LD_LIBRARY_PATH
      - LIBRARY_PATH
      ./include:
      - C_INCLUDE_PATH
      - CPLUS_INCLUDE_PATH
  packages:
    all:
      target: [x86_64_v4]
    openmpi:
      buildable: false
      prefer:
      - '+gpfs'
      externals:
      - spec: "openmpi@5.0.3%gcc@12.2.0"
        prefix: /share/apps/rocky9/general/libs/openmpi/gcc/12.2.0/5.0.3
    ucx:
      buildable: false
      externals:
      - spec: "ucx@1.16.0%gcc@12.2.0"
        prefix: /share/apps/rocky9/general/libs/ucx/gcc/12.2.0/1.16.0
  specs:
    - gcc@12.2.0
    - openmpi
  upstreams:
    apocrita:
      install_tree: /share/apps/rocky9/spack/apps
  view:
    default:
      root: .spack-env/view

If we save this as /data/scratch/${USER}/spack-environments/helloworld-gcc-ompi/spack.yaml and then activate, spec and install the environment:

Output of activate and spec Spack commands (click to expand) 
$ spack env activate -p /data/scratch/${USER}/spack-environments/helloworld-gcc-ompi
[helloworld-gcc-ompi] $ spack spec
Input spec
--------------------------------
 -   openmpi

Concretized
--------------------------------
[e]  openmpi@5.0.3%gcc@12.2.0~atomics~cuda+gpfs~internal-hwloc~internal-libevent~internal-pmix~java~legacylaunchers~lustre~memchecker~openshmem~orterunprefix~romio+rsh~static+vt+wrapper-rpath build_system=autotools fabrics=none romio-filesystem=none schedulers=none arch=linux-rocky9-x86_64_v4

Input spec
--------------------------------
 -   gcc@12.2.0

Concretized
--------------------------------
[^]  gcc@12.2.0%gcc@11.4.1~binutils+bootstrap~graphite~nvptx~piclibs~profiled~strip build_system=autotools build_type=RelWithDebInfo languages='c,c++,fortran' arch=linux-rocky9-x86_64_v4
[^]      ^diffutils@3.10%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^gawk@5.3.0%gcc@11.4.1~nls build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^libsigsegv@2.14%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^readline@8.2%gcc@11.4.1 build_system=autotools patches=bbf97f1 arch=linux-rocky9-x86_64_v4
[^]      ^gcc-runtime@11.4.1%gcc@11.4.1 build_system=generic arch=linux-rocky9-x86_64_v4
[e]      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^gmake@4.4.1%gcc@11.4.1~guile build_system=generic arch=linux-rocky9-x86_64_v4
[^]      ^gmp@6.2.1%gcc@11.4.1+cxx build_system=autotools libs=shared,static patches=69ad2e2 arch=linux-rocky9-x86_64_v4
[^]          ^autoconf@2.72%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^automake@1.16.5%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^m4@1.4.19%gcc@11.4.1+sigsegv build_system=autotools patches=9dc5fbd,bfdffa7 arch=linux-rocky9-x86_64_v4
[^]      ^libtool@2.4.7%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^findutils@4.9.0%gcc@11.4.1 build_system=autotools patches=440b954 arch=linux-rocky9-x86_64_v4
[^]      ^mpc@1.3.1%gcc@11.4.1 build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]      ^mpfr@4.2.1%gcc@11.4.1 build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]          ^autoconf-archive@2023.02.20%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^perl@5.38.0%gcc@11.4.1+cpanm+opcode+open+shared+threads build_system=generic patches=714e4d1 arch=linux-rocky9-x86_64_v4
[^]          ^berkeley-db@18.1.40%gcc@11.4.1+cxx~docs+stl build_system=autotools patches=26090f4,b231fcc arch=linux-rocky9-x86_64_v4
[^]          ^bzip2@1.0.8%gcc@11.4.1~debug~pic+shared build_system=generic arch=linux-rocky9-x86_64_v4
[^]          ^gdbm@1.23%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^texinfo@7.0.3%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^gettext@0.22.5%gcc@11.4.1+bzip2+curses+git~libunistring+libxml2+pic+shared+tar+xz build_system=autotools arch=linux-rocky9-x86_64_v4
[^]              ^libxml2@2.10.3%gcc@11.4.1+pic~python+shared build_system=autotools arch=linux-rocky9-x86_64_v4
[^]              ^tar@1.34%gcc@11.4.1 build_system=autotools zip=pigz arch=linux-rocky9-x86_64_v4
[^]                  ^pigz@2.8%gcc@11.4.1 build_system=makefile arch=linux-rocky9-x86_64_v4
[^]              ^xz@5.4.6%gcc@11.4.1~pic build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]          ^ncurses@6.5%gcc@11.4.1~symlinks+termlib abi=none build_system=autotools patches=7a351bc arch=linux-rocky9-x86_64_v4
[^]              ^pkgconf@2.2.0%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^zlib-ng@2.1.6%gcc@11.4.1+compat+new_strategies+opt+pic+shared build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^zstd@1.5.6%gcc@11.4.1+programs build_system=makefile compression=none libs=shared,static arch=linux-rocky9-x86_64_v4
Output of spack install (click to expand) 
[helloworld-gcc-ompi] $ spack install -j ${NSLOTS}
==> Concretized openmpi
[e]  f6rfqov  openmpi@5.0.3%gcc@12.2.0~atomics~cuda+gpfs~internal-hwloc~internal-libevent~internal-pmix~java~legacylaunchers~lustre~memchecker~openshmem~orterunprefix~romio+rsh~static+vt+wrapper-rpath build_system=autotools fabrics=none romio-filesystem=none schedulers=none arch=linux-rocky9-x86_64_v4

==> Concretized gcc@12.2.0
[^]  6frskzg  gcc@12.2.0%gcc@11.4.1~binutils+bootstrap~graphite~nvptx~piclibs~profiled~strip build_system=autotools build_type=RelWithDebInfo languages='c,c++,fortran' arch=linux-rocky9-x86_64_v4
[^]  7zermel      ^diffutils@3.10%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  cfhpr5n      ^gawk@5.3.0%gcc@11.4.1~nls build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  m2gvtuy          ^libsigsegv@2.14%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  ea7drzj          ^readline@8.2%gcc@11.4.1 build_system=autotools patches=bbf97f1 arch=linux-rocky9-x86_64_v4
[^]  llid4hw      ^gcc-runtime@11.4.1%gcc@11.4.1 build_system=generic arch=linux-rocky9-x86_64_v4
[e]  xri56vc      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  xchit5a      ^gmake@4.4.1%gcc@11.4.1~guile build_system=generic arch=linux-rocky9-x86_64_v4
[^]  ibyfd4t      ^gmp@6.2.1%gcc@11.4.1+cxx build_system=autotools libs=shared,static patches=69ad2e2 arch=linux-rocky9-x86_64_v4
[^]  h32ralr          ^autoconf@2.72%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  y5sqj65          ^automake@1.16.5%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  fdljdyg          ^m4@1.4.19%gcc@11.4.1+sigsegv build_system=autotools patches=9dc5fbd,bfdffa7 arch=linux-rocky9-x86_64_v4
[^]  c43op4r      ^libtool@2.4.7%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  62lolye          ^findutils@4.9.0%gcc@11.4.1 build_system=autotools patches=440b954 arch=linux-rocky9-x86_64_v4
[^]  cbwhyvl      ^mpc@1.3.1%gcc@11.4.1 build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]  u7r7eqd      ^mpfr@4.2.1%gcc@11.4.1 build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]  oo5zdhe          ^autoconf-archive@2023.02.20%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  eyk53wh      ^perl@5.38.0%gcc@11.4.1+cpanm+opcode+open+shared+threads build_system=generic patches=714e4d1 arch=linux-rocky9-x86_64_v4
[^]  cogxxtx          ^berkeley-db@18.1.40%gcc@11.4.1+cxx~docs+stl build_system=autotools patches=26090f4,b231fcc arch=linux-rocky9-x86_64_v4
[^]  uj4wyhx          ^bzip2@1.0.8%gcc@11.4.1~debug~pic+shared build_system=generic arch=linux-rocky9-x86_64_v4
[^]  bx77xc6          ^gdbm@1.23%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  lpjte4q      ^texinfo@7.0.3%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  udcuonu          ^gettext@0.22.5%gcc@11.4.1+bzip2+curses+git~libunistring+libxml2+pic+shared+tar+xz build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  q6zmsq6              ^libxml2@2.10.3%gcc@11.4.1+pic~python+shared build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  ivzmnos              ^tar@1.34%gcc@11.4.1 build_system=autotools zip=pigz arch=linux-rocky9-x86_64_v4
[^]  somkvv4                  ^pigz@2.8%gcc@11.4.1 build_system=makefile arch=linux-rocky9-x86_64_v4
[^]  rwn7pno              ^xz@5.4.6%gcc@11.4.1~pic build_system=autotools libs=shared,static arch=linux-rocky9-x86_64_v4
[^]  4n2uzha          ^ncurses@6.5%gcc@11.4.1~symlinks+termlib abi=none build_system=autotools patches=7a351bc arch=linux-rocky9-x86_64_v4
[^]  7wg26bz              ^pkgconf@2.2.0%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  g2yruc3      ^zlib-ng@2.1.6%gcc@11.4.1+compat+new_strategies+opt+pic+shared build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  my7tyw6      ^zstd@1.5.6%gcc@11.4.1+programs build_system=makefile compression=none libs=shared,static arch=linux-rocky9-x86_64_v4

[+] /share/apps/rocky9/general/libs/openmpi/gcc/12.2.0/5.0.3 (external openmpi-5.0.3-f6rfqovydeohhtdzs6yl2qiro2hxltpm)
[+] /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-11.4.1/gcc/12.2.0-6frskzg
==> Updating view at /data/scratch/abc123/spack-environments/helloworld-gcc-ompi/.spack-env/view

To ensure that all required environment variables are activated for Open MPI, it is best to deactivate the environment and then re-activate it again to enable them:

spack env deactivate
spack env activate -p /data/scratch/${USER}/spack-environments/helloworld-gcc-ompi

Create a file called hello_world_mpi.cpp in a folder of your choice, for this example we will use the path:

/data/scratch/${USER}/hello_world_cpp/hello_world_mpi.cpp

Use the sample code from the previously mentioned example:

hello_world_mpi.cpp (click to expand) 
#include <stdio.h>
#include <mpi.h>

int main(int argc, char** argv){
    int process_Rank, size_Of_Cluster;

    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &size_Of_Cluster);
    MPI_Comm_rank(MPI_COMM_WORLD, &process_Rank);

    for(int i = 0; i < size_Of_Cluster; i++){
        if(i == process_Rank){
            printf("Hello World from process %d of %d\n", process_Rank, size_Of_Cluster);
        }
        MPI_Barrier(MPI_COMM_WORLD);
    }

    MPI_Finalize();
    return 0;
}

Then, much as our previous cmake example, the Spack environment enables us to compile the simple example:

hello_world_ompi.exe compile and install 
[helloworld-gcc-ompi] $ cd /data/scratch/${USER}/hello_world_cpp
[helloworld-gcc-ompi] [hello_world_cpp] $ mpic++ hello_world_mpi.cpp -o hello_world_ompi.exe

You can then run the compiled executable as instructed:

hello_world_ompi.exe output 
[helloworld-gcc-ompi] [hello_world_cpp] $ mpirun -np ${NSLOTS} ./hello_world_ompi.exe
Hello World from process 0 of 8
Hello World from process 1 of 8
Hello World from process 2 of 8
Hello World from process 3 of 8
Hello World from process 4 of 8
Hello World from process 5 of 8
Hello World from process 6 of 8
Hello World from process 7 of 8
Hello World from process 8 of 8

Intel and Intel MPI example

Let's run through the same thing again, but this time we will compile using Intel and Intel MPI.

A spack.yaml template for compiling and running this example using Intel and Intel MPI can be found in the spack-config-templates repository inside the environment-templates sub-directory for the version of Spack you are using - called helloworld-intel-intelmpi.yaml:

Contents of spack.yaml for Hello World Intel/Intel MPI (click to expand) 
spack:
  compilers:
  - compiler:
      spec: oneapi@=2024.1.0
      paths:
        cc: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-compilers/2024.1.0-bdqsx5f/compiler/2024.1/bin/icx
        cxx: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-compilers/2024.1.0-bdqsx5f/compiler/2024.1/bin/icpx
        f77: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-compilers/2024.1.0-bdqsx5f/compiler/2024.1/bin/ifx
        fc: /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-compilers/2024.1.0-bdqsx5f/compiler/2024.1/bin/ifx
      flags: {}
      operating_system: rocky9
      target: x86_64
      modules: []
      environment: {}
      extra_rpaths: []
  concretizer:
    unify: true
  config:
    install_tree:
      root: /data/scratch/${USER}/spack/apps
      projections:
        ^mpi: '{architecture}/{compiler.name}-{compiler.version}/{name}/{version}-{^mpi.name}-{^mpi.version}-{hash:7}'
        all: '{architecture}/{compiler.name}-{compiler.version}/{name}/{version}-{hash:7}'
    license_dir: /data/scratch/${USER}/spack/licenses
    source_cache: /data/scratch/${USER}/spack/cache
  modules:
    prefix_inspections:
      ./share/aclocal:
      - ACLOCAL_PATH
      ./lib:
      - LD_LIBRARY_PATH
      - LIBRARY_PATH
      ./lib64:
      - LD_LIBRARY_PATH
      - LIBRARY_PATH
      ./include:
      - C_INCLUDE_PATH
      - CPLUS_INCLUDE_PATH
  packages:
    all:
      target: [x86_64_v4]
  specs:
    - intel-oneapi-compilers
    - intel-oneapi-mpi
  upstreams:
    apocrita:
      install_tree: /share/apps/rocky9/spack/apps
  view:
    default:
      root: .spack-env/view

So, what has changed?

  • The compilers section just lists oneapi@=2024.1.0, the Intel compiler
  • The packages section no longer lists our external Open MPI and UCX versions...
  • ...because we have replaced Open MPI with intel-oneapi-mpi in our specs
  • intel-oneapi-compilers replaces the gcc@12.2.0 we had in the first GCC/Open MPI example above
  • Remember, Intel packages commence with intel-oneapi-* - for more information refer back to the Custom Scopes tutorial

If we save this as /data/scratch/${USER}/spack-environments/helloworld-intel-intelmpi/spack.yaml and then activate, spec and install the environment:

Output of activate and spec Spack commands (click to expand) 
$ spack env activate -p /data/scratch/${USER}/spack-environments/helloworld-intel-intelmpi
[helloworld-intel-intelmpi] $ spack spec
Input spec
--------------------------------
 -   intel-oneapi-mpi

Concretized
--------------------------------
[^]  intel-oneapi-mpi@2021.12.1%gcc@12.2.0+envmods~external-libfabric~generic-names~ilp64 build_system=generic arch=linux-rocky9-x86_64_v4
[^]      ^gcc-runtime@12.2.0%gcc@12.2.0 build_system=generic arch=linux-rocky9-x86_64_v4
[e]      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4

Input spec
--------------------------------
 -   intel-oneapi-compilers

Concretized
--------------------------------
[^]  intel-oneapi-compilers@2024.1.0%gcc@12.2.0+envmods build_system=generic arch=linux-rocky9-x86_64_v4
[^]      ^gcc-runtime@12.2.0%gcc@12.2.0 build_system=generic arch=linux-rocky9-x86_64_v4
[e]      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]      ^patchelf@0.17.2%gcc@12.2.0 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]          ^gmake@4.4.1%gcc@11.4.1~guile build_system=generic arch=linux-rocky9-x86_64_v4
[^]              ^gcc-runtime@11.4.1%gcc@11.4.1 build_system=generic arch=linux-rocky9-x86_64_v4
Output of spack install (click to expand) 
[helloworld-intel-intelmpi] [abc123@ddy58 ~]$ spack install -j $NSLOTS
==> Concretized intel-oneapi-mpi
[^]  kmurskw  intel-oneapi-mpi@2021.12.1%gcc@12.2.0+envmods~external-libfabric~generic-names~ilp64 build_system=generic arch=linux-rocky9-x86_64_v4
[^]  w77gg5r      ^gcc-runtime@12.2.0%gcc@12.2.0 build_system=generic arch=linux-rocky9-x86_64_v4
[e]  xri56vc      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4

==> Concretized intel-oneapi-compilers
[^]  bdqsx5f  intel-oneapi-compilers@2024.1.0%gcc@12.2.0+envmods build_system=generic arch=linux-rocky9-x86_64_v4
[^]  w77gg5r      ^gcc-runtime@12.2.0%gcc@12.2.0 build_system=generic arch=linux-rocky9-x86_64_v4
[e]  xri56vc      ^glibc@2.34%gcc@11.4.1 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  nlkm7ih      ^patchelf@0.17.2%gcc@12.2.0 build_system=autotools arch=linux-rocky9-x86_64_v4
[^]  xchit5a          ^gmake@4.4.1%gcc@11.4.1~guile build_system=generic arch=linux-rocky9-x86_64_v4
[^]  llid4hw              ^gcc-runtime@11.4.1%gcc@11.4.1 build_system=generic arch=linux-rocky9-x86_64_v4

[+] /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-mpi/2021.12.1-kmurskw
[+] /share/apps/rocky9/spack/apps/linux-rocky9-x86_64_v4/gcc-12.2.0/intel-oneapi-compilers/2024.1.0-bdqsx5f
==> Updating view at /data/scratch/abc123/spack-environments/helloworld-intel-intelmpi/.spack-env/view

To ensure that all required environment variables are activated for Intel and Intel MPI, it is best to deactivate the environment and then re-activate it again to enable them:

spack env deactivate
spack env activate -p /data/scratch/${USER}/spack-environments/helloworld-intel-intelmpi

We can use the same hello_world_mpi.cpp as above to again compile the simple example (this time we will use the name hello_world_intelmpi.exe):

Use mpiicpx instead of mpiicc

The linked example uses mpiicc to compile which is now deprecated. As we are using version 2024.1.0 for this tutorial, you will need to use mpiicpx instead, as detailed below.

hello_world_intelmpi.exe compile and install 
[helloworld-intel-intelmpi] $ cd /data/scratch/${USER}/hello_world_cpp
[helloworld-intel-intelmpi] [hello_world_cpp] $ mpiicpx hello_world_mpi.cpp -o hello_world_intelmpi.exe

You can again run the compiled executable as instructed:

hello_world_intelmpi.exe output 
[helloworld-intel-intelmpi] [hello_world_cpp] $ mpirun -np ${NSLOTS} ./hello_world_intelmpi.exe
Hello World from process 0 of 8
Hello World from process 1 of 8
Hello World from process 2 of 8
Hello World from process 3 of 8
Hello World from process 4 of 8
Hello World from process 5 of 8
Hello World from process 6 of 8
Hello World from process 7 of 8
Hello World from process 8 of 8