[SciPy-Dev] disabling Accelerate on OS X

Pauli Virtanen pav@iki...
Thu Jun 13 02:40:07 CDT 2013

Jack Howarth <howarth <at> bromo.med.uc.edu> writes:
> Just to be clear, have standalone test cases that exhibit
> these single and double precision failures been submitted?

The issue is not really precision problems --- rather, they are
due to an incompatible Fortran ABI in Accelerate.

If you compile Scipy with -ff2c Fortran compiler flag enabled,
(e.g. export FOPT="-ff2c -O2") the errors reportedly go away.
Apple would be justified in responding "just use correct compiler

However, having numpy.distutils provide this flag can then cause
issues if you link with Fortran libraries compiled without it,
so I'm thinking that taking care of keeping their build environment
in a single Fortran ABI is best left to whoever does the building,
and numpy.distutils should just check that the Fortran ABI is
compatible during build.

Scipy does have some compatibility code that works around the
incompatible ABI even without this compiler flag, and things
worked fine up to OSX 10.6, but apparently after that Apple
changed something (perhaps harmonized some routines to g77 ABI).

Pauli Virtanen

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