Re: OSX blas wrapper for release (Re: plans for release)

[Richard Campbell]

On Feb 4, 2011, at 10:47 AM, Richard Campbell wrote:

> 
> On Feb 4, 2011, at 9:58 AM, Jarno Rajahalme wrote:
> 
>> 
>> On Feb 3, 2011, at 22:24 , ext John W. Eaton wrote:
>> 
>>> On  3-Feb-2011, Richard Campbell wrote:
>>> 
>>> | I'd like to see Jarno's blaswrap.c included in the Octave source, and used
>>> | automatically when the user runs ./configure for a 64-bit Octave on a 
>>> machine
>>> | where the Apple-provided BLAS is the only one detected.
>>> 
>>> It would probably be good to also verify that the detected BLAS won't
>>> work, so that if it is fixed in the future the wrapper won't be
>>> needed.
>>> 
>> 
>> After some deliberation I thought the best place for the wrapper is 
>> libcruft/misc/. This avoids managing an additional dylib, and is a no-op, 
>> when the wrapper is not needed.
>> 
>> Here is a patch to configure.ac and libcruft/misc/module.mk that:
>> 
>> 0) removes -arch flags from FLTK flags to allow compilation with non-Apple 
>> GCC
>> 1) if blas is found to be incompatible, tries again with -ff2c
>> 2) if it is still incompatible, and platform is darwin, compiles 
>> libcruft/misc/blaswrap.c, and tries with that
>> - if successful, defines USE_BLASWRAP, so that libcruft will be built to 
>> contain the wrapper.
>> 
>> Steps to apply:
>> 
>> 1. Patch configure.ac and libcruft/misc/module.mk:
>> 
>> $ patch -p 1 < blaswrap.patch
>> 
>> <blaswrap.patch>
>> 
>> The same patch also updates libcruft/misc/module.mk to include blaswrap.c
>> 
>> 
>> 2. Place blaswrap.c into libcruft/misc
>> 
>> $ cp blaswrap.c /libcruft/misc/.
>> 
>> <blaswrap.c>
>> 
>> blaswrap.c is updated to work from within libcruft (included, save as 
>> libcruft/misc/blaswrap.c)
>> 
>> The updated wrapper should work also with 32-bit builds. But since the 
>> "-ff2c" option is tested first, the wrapper will NOT be used on 32-bit 
>> builds.
>> 
>> 
>> 3. Have your config.h.in updated:
>> 
>> $ ./autogen.sh
>> 
>> This works only for the development version. For a snapshot, you need to do 
>> this manually. Ddd these lines to config.h.in after line 2203:
>> 
>> /* Define this if BLAS functions need to be wrapped (potentially needed for
>> OSX only). */
>> undef USE_BLASWRAP
>> 
>> Please note that if your config.h.in does not get updated (see above), the 
>> configure will succeed, but the wrapper will be ignored during build, likely 
>> causing a crash.
>> 
>> 
>> 4. ./configure <your config options>
>> 
>> Note that there is no need for any blas options here.
>> 
>> 
>> 5. make -j2 check
>> 
>> If you built on 32-bit OSX, your FFLAGS should now have "-ff2c", and 
>> BLAS_LIBS should contain "-framework vecLib"
>> 
>> If you built on 64-bit OSX, config.h should define USE_BLASWRAP, and 
>> BLAS_LIBS should contain "-framework vecLib".
>> 
>> Additionally, after you make octave, you should see that libcruft defines 
>> ("T") the symbol _cdotu_, while without the wrapper it remains undefined 
>> ("U"):
>> 
>> $ nm -g libcruft/.libs/libcruft.dylib | grep -i _cdotu_
>> 00000000000821e0 T _cdotu_
>> $ 
>> 
>> 
>> I have tested this on OSX 10.6.6, with gcc-4.2 and gcc-mp-4.5, building 
>> 64-bit only. Someone else should test this on a 32-bit build.
>> 
>> NOTE: if you have atlas installed, it will likely be used instead of the 
>> wrapper. I think this is as it should be.
>> 
>> Finally, as I have never pushed anything on Octave source base, I'd be happy 
>> if someone else does it.
>> 
>> Jarno
>> 
> 
> Jarno,
> 
> Great, thanks for your effort. I hope this makes it into the release this 
> weekend. I also haven't figured out how to make a Mercurial changeset and I 
> don't think I will in time. Anyone?
> 
> Campbell


Okay, I followed the instructions in the Octave pdf to make a Mercurial 
changeset. It's attached.

I don't think it actually puts the blaswrap.c file in the source tree, though.

Campbell

jarnoblaswrap.diff
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