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Intel compilers

The Intel compoler suite includes front ends for the C (icc), C++ (icx), and Fortran (ifort) programming languages.

Choose a version

The Intel compilers are available from the intel module. This module loads the default version of the compiler.

$ module load intel

If you wish to use an older or newer version, you can list the available version with

$ module spider intel

and then switch to the desired version using

$ module swap intel intel/<version>

OpenMP Support

OpenMP is turned off by default. You can turn it on using the -qopenmp flag.

Optimization options

:material-help-circle-outline: man icc - man ifort

The default optimization level of the Intel compiler is -O2 -fp-model=fast. Therefore the most essential optimization flags are set by default:

-O2 -fp-model=fast
  • the -O2 option performs nearly all supported optimizations

  • the -fp-model=fast relax the IEEE specifications for math functions. This option can produce incorrect results, don’t use this flag if your code is sensitive to floating-point optimizations.

  • Intel documentation about optimization options

Compiler Feedback

Debugging

To ease a debugging process, it is useful to generate an executable containing debugging information. For this purpose, you can use the -g option.

Most of the time, the debug information works best at low levels of code optimization, so consider using the -O0 level. The -g options can be specified on a per-file basis so that only a small part of your application incurs the debugging penalty.