[Bug 363510] [NEW] Errors in single-precision BLAS (libatlas3gf-sse)

[Pauli Virtanen]

Public bug reported:

At least the single-precision complex arithmetic in libatlas3gf-sse
3.6.0-22ubuntu2 yields completely invalid results. A test program
demonstrating the errors is attached.

This issue appears to be specific to the SSE version of Atlas.

Would it be possible to add some sanity checks to Ubuntu/Debian's Atlas
build, so that this type of problems would be detected and hosed
packages wouldn't make it into distribution? Atlas is an important
component in many scientific applications, and bugs in the shipped
version will affect many programs down the stream.

    ***

Example of output from the simple test program on this platform:

$ gfortran -o test test.f -lblas
$ ldd test
	linux-gate.so.1 =>  (0xffffe000)
	libblas.so.3gf => /usr/lib/sse/atlas/libblas.so.3gf (0xb7bc6000)
	libgfortran.so.3 => /usr/lib/libgfortran.so.3 (0xb7b12000)
	libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0xb7aec000)
	libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7add000)
	libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0xb797a000)
	/lib/ld-linux.so.2 (0xb7fb8000)
$ ./test  # this uses libatlas3gf-sse 3.6.0-22ubuntu2
 failure
 - complex*8:   (  4.0000000    ,  6.9998479    )
 - complex*16:  ( -4.0000000000000000     ,  12.000000000000000     )
$ LD_PRELOAD=/usr/lib/libblas.so.3.0 ./test   # use refblas3 1.2-8ubuntu2
 success
$ LD_PRELOAD=/usr/lib/atlas/libblas.so.3gf ./test  # use libatlas3gf-base 3.6.0-22ubuntu2
 success

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
NonfreeKernelModules: nvidia
Package: libatlas3gf-sse 3.6.0-22ubuntu2
ProcEnviron:
 LC_COLLATE=C
 PATH=(custom, user)
 LANG=fi_FI.UTF-8
 SHELL=/bin/bash
SourcePackage: atlas
Uname: Linux 2.6.28-11-generic i686

** Affects: atlas (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386

-- 
Errors in single-precision BLAS (libatlas3gf-sse)
https://bugs.launchpad.net/bugs/363510
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