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by cdavid 5274 days ago
Apple did not spent a considerable amount of time tunning BLAS - they just took Atlas, an widely used open source implementation of blas/lapack (and took care of making sure it does not look like ATLAS at first glance, although a simple look at nm will show it is atlas all the way down).
1 comments
stephencanon 5274 days ago
The OS X BLAS was once ATLAS all the way down (and I see no reason to believe that any effort was made to hide that fact), but that's no longer true. A glance at nm on Lion shows that there's some ATLAS in there, but quite a lot of not-ATLAS too.
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cdavid 5274 days ago
It is mentioned nowhere in accelerate framework that it uses atlas, and they removed functions like ATL_buildinfo. I doubt it has changed much in the last 5 years as well, and I am not sure what makes you think there is ( significant) non-atlas code in there ? Besides symbols starting with ATL, I see mostly the BLAS/LAPACK API, although I did not try to check very carefully.
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stephencanon 5273 days ago
Besides the ATL-prefixed symbols, there are are numerous APL-prefixed symbols, as well as many _block_ symbols which indicate extensive use of GCD in the level 3 routines (and which ATLAS doesn't use).
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