[Pkg-octave-commit] [SCM] Debian packaging for octave branch, master, updated. 3.2.2-2-102-g2b393c2

Wed Dec 7 17:56:11 UTC 2011

The following commit has been merged in the master branch:
commit 93b66e5787067979d29b692be854bba987531d4f
Author: Thomas Weber <tweber at debian.org>
Date:   Mon Nov 14 22:42:10 2011 +0100

    Revamp README.Atlas to current situation on Debian
    
    Git-Dch: Ignore

diff --git a/debian/README.Atlas b/debian/README.Atlas
index 21579fb..90a2e4f 100644
--- a/debian/README.Atlas
+++ b/debian/README.Atlas
@@ -1,126 +1,9 @@
 
-	     Notes on using Atlas libs with GNU Octave and GNU R
+	     Notes on using Atlas libs with GNU Octave
 
-I. Overview
+In order to speed up Octave's BLAS and  LAPACK operation, you can install the
+ATLAS packages (libatlas3gf-base at the time of writing). Octave should
+automatically pick up the faster libraries.
 
-As of the Debian releases 2.1.34-6 (for GNU Octave) and 1.3.0-3 (for GNU R),
-both Octave and R can be used with Atlas, the Automatically Tuned Linear
-Algebra Software, in order to obtain much faster linear algebra operations.
 
-To make use of Atlas, Debian users need to install the Atlas libraries for
-their given cpu architecture. Concretely, one of
-
-    atlas2-base - Automatically Tuned Linear Algebra Software
-    atlas2-p3 - Automatically Tuned Linear Algebra Software
-    atlas2-p4 - Automatically Tuned Linear Algebra Software
-    atlas2-athlon - Automatically Tuned Linear Algebra Software
-
-must be installed. Here, 'base' provides generic libraries which run on all
-platforms whereas 'p3', 'p4' and 'athlon' stand for the Pentium III and IV as
-well as the AMD Athlon, respectively.  The actual libraries are installed in
-/usr/lib/atlas (in the case of 'base') and in /usr/lib/$arch/atlas for the
-cpu-specific versions. Here $arch stands for the cpu code used by the kernel
-and shown in /proc/cpuinfo.
-
-The Atlas libraries can be loaded dynamically instead of the (non-optimised)
-blas libraries against which both Octave and R are compiled.
-
-Section III below briefly describes how Atlas libraries can be compiled for
-your specific machine to further optimise performance.
-
-II. Using the Atlas libraries
-
-II.A New default behaviour with automatic loading of the Atlas libraries
-
-In order to have the libraries loaded at run-time, the location needs to be
-communicated to the dynamic linker/loader. As of the Debian release
-libc6_2.2.4-5 of the glibc library, a patch to ldconfig automates the use of
-the Atlas library. If an Atlas package is installed, and correctly registered
-in /etc/ld.so.conf as done by its postinst script, ldconfig will
-automatically load the Atlas' version of the Blas instead of the (slower)
-default Blas.
-
-The following text is hence only relevant for systems which have not yet
-upgraded to libc6_2.2.4-5 or later.
-
-II.B Old behaviour requiring LD_LIBRARY_PATH for Octave
-
-For Octave, use the variable LD_LIBRARY_PATH. On a computer with the
-atlas2-base package:
-
-    $ LD_LIBRARY_PATH=/usr/lib/atlas octave2.1 -q
-    octave2.1:1> X=randn(1000,1000);t=cputime();Y=X'*X;cputime-t
-    ans = 7.9600
-
-    $ edd at homebud:~> octave2.1 -q
-    octave2.1:1> X=randn(1000,1000);t=cputime();Y=X'*X;cputime-t
-    ans = 61.520
-
-For R version 1.3.0-4, the R_LD_LIBRARY_PATH variable has to be used, and its
-value needs to be copied out of /usr/bin/R (or edited therein). For R version
-1.3.1 or later this is done automatically in the R startup shell script.  For
-an Athlon machine, and with the explicit definition which is no longer needed
-as of R 1.3.1, the example becomes
-
-    $ R_LD_LIBRARY_PATH=/usr/lib/R/bin:/usr/local/lib:/usr/X11R6/lib:/usr/lib/3dnow/atlas:/usr/lib:/usr/X11R6/lib:/usr/lib/gcc-lib/i386-linux/2.95.4:. R --vanilla -q
-    > mm <- matrix(rnorm(10^6), ncol = 10^3)
-    > system.time(crossprod(mm))
-    [1] 2.38 0.04 2.84 0.00 0.00
-
-    $ R --vanilla -q
-    > mm <- matrix(rnorm(10^6), ncol = 10^3)
-    > system.time(crossprod(mm))
-    [1] 28.28  0.08 33.54  0.00  0.00
-    > 
-
-Running such a small example is highly recommded to ascertain that the
-libraries are indeed found, and to "prove" that the speed gain is real (and
-significant) for problems of at least a medium size as the 1000x1000 examples
-above.
-
-Note that the example use "/usr/lib/atlas" for the atlas2-base package;
-Athlon users should employ "/usr/lib/3dnow/atlas", Pentium III users should
-employ "/usr/lib/xmm/atlas" and Pentium IV users should employ
-"/usr/lib/26/atlas".
-
-Lastly, it should be pointed out that it is probably worthwhile to locally
-compile, and thereby optimise, the Atlas libraries if at least a moderately
-intensive load is expected. This is described in the next section.
-
-III. Locally compiling the Atlas libraries
-
-The Debian Atlas packages have been setup to allow for local recompilation of
-the Atlas libraries. This way the behaviour will be tuned exactly to the
-specific CPU rather than the broader class of CPUs. It has been reported that
-this can increase performance by a further 12% on the examples above.
-Detailed instructions are in /usr/share/doc/atlas2-base/README.debian.gz but
-the process is essentially the following  [ courtesy of Doug Bates ]
-
-   apt-get source atlas2-base
-   cd atlas2-$VERSION
-   fakeroot debian/rules/custom
-   # wait for a *very* long time
-   dpkg -i ../atlas2-base*.deb
-
-
-IV.  See also
-
-The Atlas packages have a very detailed README.Debian file which should be
-consulted; it also details local recompilation. Sources and documentation for
-Atlas are at   http://www.netlib.org/atlas.
-
-
-V.  Acknowledgements
-
-Camm Maguire developed the scheme of overloading Atlas over the default blas
-libraries and deserves all the credit. Many thanks to John Eaton for helping
-debug some errors in the initial setup, and to Doug Bates for work on the R
-package. Special thanks to Ben Collins for providing a patched ldconfig as
-part of the libc6 package.
-
-
-Initial version
- -- Dirk Eddelbuettel <edd at debian.org>  Tue, 21 Aug 2001 21:37:15 -0500
-
-First updated
- -- Dirk Eddelbuettel <edd at debian.org>  Sun, 11 Nov 2001 11:03:19 -0600
+ -- Thomas Weber <tweber at debian.org>  Mon, 14 Nov 2011 22:41:35 +0100 

-- 
Debian packaging for octave

