Changes between Version 7 and Version 8 of CompilingPdaf
- Timestamp:
- Jan 9, 2022, 4:38:33 PM (3 years ago)
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CompilingPdaf
v7 v8 63 63 == Notes == 64 64 65 * '''Note on parallelization:''' PDAF is generally intended for parallel computing using MPI. Before PDAF V2.0 it was also possible to compile PDAF without MPI by using a stub library that simulated the behavior for MPI for a single process that we provided with PDAF. With PDAF V2., we revised the MPI implementation and removed this option. Given that it is today extremely easy to install an MPI library (it is virtually always available as a package in any Linux distribution and standard on cluster computers) we prefer not to invest in maintaining and upgrading the MPI stub library.65 * '''Note on parallelization:'''[[BR]] PDAF is generally intended for parallel computing using MPI. Before PDAF V2.0 it was also possible to compile PDAF without MPI by using a stub library that simulated the behavior for MPI for a single process that we provided with PDAF. With PDAF V2., we revised the MPI implementation and removed this option. Given that it is today extremely easy to install an MPI library (it is virtually always available as a package in any Linux distribution and standard on cluster computers) we prefer not to invest in maintaining and upgrading the MPI stub library. 66 66 67 * '''Note on precision of floating point variables:''' PDAF is designed to use floating point variables of double precision. However, for flexibility the variables are decared in the source code without a 'KIND' specification.67 * '''Note on precision of floating point variables:'''[[BR]] PDAF is designed to use floating point variables of double precision. However, for flexibility the variables are decared in the source code without a 'KIND' specification. 68 68 * For the compilation one has to specify that the compiler treats all 'real' variables with double precision accuracy. This is done, e.g. for gfortran by setting `-fdefault-real-8` or for ifort by setting `-r8`. In the provided include files in `make.arch/` these specifications are included. 69 69 * PDAF also supports single precision. To enable it in PDAF, one has to use the preprocessor definition `-DSNGLPREC`. Then one has to compile without the double-precision settings.