Hi
I hope the title of this message indicates my question. I am looking
for basic
array functionality in Python and it turns out that there are all these
packages which
are somehow related. Some are allegedly discontinued but still seem to
get updated. Could we start a discussion about which package will or
may or should survive ?
I started to use numarray, but I have a bug that I just cannot find a
solution for, so I started
to look around again. Basically I want to provide scripting support to
a graphics engine. All the
matrices and vectors are in C++ and all I want to do is provide an
interface to python. As a matter of fact, all of the matrix
multiplication etc, could remain in the native C++ code, but I need a
way to extend the python language with the array data type and somehow
intercept operator calls such as *,+,- ....
How is that done in the current libraries... Thx for any help.
Cheers
Jochen
Jan 21 '06
22  2005 
On Sat, 21 Jan 2006, Travis E. Oliphant wrote: J wrote:
I will just jump in an use NumPy. I hope this one will stick and evolve
into the mother of array packages. How stable is it ? For now I really
just need basic linear algebra. i.e. matrix multiplication, dot, cross
etc
There is a new release coming out this weekend. It's closer to 1.0 and
so should be more stable. It also has some speed improvements in
matrix-vector operations (if you have ATLAS BLAS --- or if you download
a binary version with ATLAS BLAS compiled in). I would wait for it.
Pardon my failure to RTFM, but does NumPy pick up the vecLib BLAS on Macs?
tom
--
It's the 21st century, man - we rue _minutes_. -- Benjamin Rosenbaum
Tom Anderson wrote: Pardon my failure to RTFM, but does NumPy pick up the vecLib BLAS on Macs?
Yes.
--
Robert Kern ro*********@gma il.com
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
"J" <js****@cs.uvic .ca> writes: I hope the title of this message indicates my question. I am looking
for basic
array functionality in Python and it turns out that there are all these
packages which
are somehow related. Some are allegedly discontinued but still seem to
get updated.
It's well explained in the homepage: numpy.scipy.org
AFAIK you should use numpy for future use.
--
Lawrence - http://www.oluyede.org/blog
"Anyone can freely use whatever he wants but the light at the end
of the tunnel for most of his problems is Python"
On Sat, 21 Jan 2006, Robert Kern wrote: Tom Anderson wrote:
Pardon my failure to RTFM, but does NumPy pick up the vecLib BLAS on Macs?
Yes.
Excellent, thanks.
tom
--
forget everything from school -- you are programmer
Robert Kern wrote: J wrote: I will just jump in an use NumPy. I hope this one will stick and evolve
into the mother of array packages.
How stable is it ? For now I really just need basic linear algebra.
i.e. matrix multiplication, dot, cross etc
Same concern for me.
I discovered recently that I could not rely on numeric anymore
because 'eigenvalue' is now broken on my platform. This bug
has been referenced but not corrected AFAIK. Too bad that
numeric is not actively maintained anymore. Easy-to-install,
good doc, well-thought interface, really good stuff !
Bye-bye Numeric !
By the way, I tried numpy 0.9.4 10 minutes ago and guess
what ? 'eigenvalue' is broken too ... (hangs forever)
I do really hope the numpy will become the robust, best-of-breed
Python Array/Matrix lib that many people are waiting for. But in
the meantime, it's back to Matlab :(
SB
Sébastien Boisgérault wrote: By the way, I tried numpy 0.9.4 10 minutes ago and guess
what ? 'eigenvalue' is broken too ... (hangs forever)
On what platform? Are you linking against an optimized BLAS? We can't fix
anything without details. I'll be happy to work with you on this bug over on the
numpy-discussion list.
--
Robert Kern ro*********@gma il.com
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter Basically all I need is vectors and 3x3 matrices.
hmm
is numpy really efficient for 3x3 (or 4x4) matrices and vectors?
IMHO an optimized matrix4x4 class can be much faster (i'm just guessing
here)
eg cgtypes is a simple c++ implementation with boost-python wrapper: http://cgkit.sourceforge.net/
Szabolcs Nagy wrote: Basically all I need is vectors and 3x3 matrices.
hmm
is numpy really efficient for 3x3 (or 4x4) matrices and vectors?
IMHO an optimized matrix4x4 class can be much faster (i'm just guessing
here)
eg cgtypes is a simple c++ implementation with boost-python wrapper:
http://cgkit.sourceforge.net/
If you're operating on a single 3x3 or 4x4 matrix, nothing you do in
Python will be "efficient" , by which I assume you mean not all that far
from C speed; the interpreter overhead is simply too high. If you can
operate on large blocks of small arrays and vectors at the same time,
which one can usually do after consuming sufficient coffee, then yes
numpy can be fast if you're careful.
-tim
Robert Kern wrote: Sébastien Boisgérault wrote:
By the way, I tried numpy 0.9.4 10 minutes ago and guess
what ? 'eigenvalue' is broken too ... (hangs forever)
On what platform? Are you linking against an optimized BLAS? We can't fix
anything without details. I'll be happy to work with you on this bug overon the
numpy-discussion list.
This is a guess, but the original poster is probably using one of the
newer (3.4.x or 4.0.x) versions of gcc. This is a known problem: https://bugzilla.redhat.com/bugzilla....cgi?id=138791
(that's one of the applicable bug reports).
A workaround to this problem is to add the option '-ffloat-store' to
your CFLAGS.
<insert "gcc 4.0 is such a disaster" rant here>
-greg
Robert Kern wrote: Sébastien Boisgérault wrote:
By the way, I tried numpy 0.9.4 10 minutes ago and guess
what ? 'eigenvalue' is broken too ... (hangs forever)
On what platform?
Linux, Mandriva 2006 (gcc 4.0.1, etc.) Are you linking against an optimized BLAS?
Nope -- I tried the basic install.
We can't fix
anything without details.
Obviously, sorry. I was not really expecting a fix,
just wanted to point out that Numpy (or Numeric)
may well not work "out of the box" today on some
platforms.
The (similar) problem has been reported (2005-07-11)
is not assigned to anybody and is still open
See: http://sourceforge.net/tracker/?grou...69&atid=101369
I'll be happy to work with you on this bug over on the
numpy-discussion list.
Great Robert, I will follow your advice then. Thanks
for the proposal. --
Robert Kern
ro*********@gma il.com
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
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