[Q-e-developers] Internal LAPACK and BLAS

[Filippo SPIGA]

Dear all,

as you probably noticed in r12944, r12939, r12929 I heavily modified some makefiles and configure options related to internal LAPACK and BLAS. I am still working on assess and verify all reproducible corner cases, who is using vendor-optimized libraries is not affected by these changes at all.

A very old BLAS locate in "archive/" has been deprecated and Netlib LAPACK has been upgraded from 3.2 to 3.6.1. Netlib LAPACK is still present under archive/ but, in case it is not, it will be downloaded and compiled automatically. Moreover modern Netlib LAPACK incorporate BLAS, there is no need of an explicit BLAS archive inside the QE distribution.

The configure behaviour reflect this modern setup. "--with-internal-blas" and "--with-internal-lapack" have been collapsed into "--with-netlib". Nowadays BLAS and LAPACK are always present "together". If this is not the case, the system is odd and (the system) must be fixed.

The plan in the next few days is to clean up the make.inc to reflect this changes.  The  variables "LAPACK_LIBS_SWITCH" and "LAPACK_LIBS_SWITCH" inside make.inc will disappear and replaced by a single "NETLIBS_SWITCH". Change yet to be made in the next few days. At the same time, some obsolete cases covered by the configure ("necsx", "aix", "sparc") will be deprecated making the BLAS/LAPACK detection proces a bit more light and lean.

Cheers

--
Filippo SPIGA ~ Quantum ESPRESSO Foundation ~ http://www.quantum-espresso.org