Mailman 3 September 2000 - NumPy-Discussion

Re: [Numpy-discussion] Da Blas
by Frank Horowitz Jan. 2, 2001

Jan. 2, 2001

At 3:14 PM -0700 14/9/00, <dubois(a)users.sourceforge.net> wrote: >Well, I certainly didn't mean to flame anyone in particular, so I'm sorry >that Frank was offended. Publicly apologized, and publicly accepted. I'm sorry I lost my cool. Ray Beausoleil and I are having a look at this too. He's coming at the problem from a Windows perspective, and I'm coming at it from a Linux/Unix perspective. It's going to be a little slow going for me at first, since it appears that I'm going to have to get my head around the distutils way of doing things.... Just in case it saves anyone else following a false lead, yes, there is a bug in the (Linux Mandrake 7.1; but probably any unix-ish box) compile line for building the lapack_lite.so shared library (i.e. what is generated on my box is "-L/usr/lib-llapack" which obviously is missing a blank before the "-llapack" substring). However, when I coerced the distutils system to get around that bug (by specifying "/usr/lib " with a trailing blank for the BLASLIBDIR and LAPACKLIBDIR variables in setup.py) the same problem (i.e. an "ImportError: /usr/lib/liblapack.so.3: undefined symbol: e_wsfe" in importing lapack_lite) ultimately manifested itself. So my advice is not to bother tracking that one down (although it probably should be reported as a bug in distutils, since adding that trailing blank algorithmically instead of in a user modifiable configuration string is the "right thing to do", TM.). I'm still puzzled by Thomas Breul's report of preloading an f2c library squashing the bug under RedHat 6.2(?). That does not work under Mandrake, although clearly there is some bloody symbol table missing from somewhere. The trouble is to find out where, and then to coerce distutils to deal with that in a portable way... Frank -- -- Frank Horowitz frank(a)ned.dem.csiro.au CSIRO-Exploration & Mining, PO Box 437, Nedlands, WA 6009, AUSTRALIA Direct: +61 8 9284 8431; FAX: +61 8 9389 1906; Reception: +61 8 9389 8421

4 4

precompiled binary for 17
by Pete Shinners Sept. 29, 2000

Sept. 29, 2000

i've compiled my own numeric, and i thought i'd offer it back for other win users. i haven't seen a precompiled binary package for win32 yet, so maybe this can get added to sourceforge? if not, here's a link that'll work for a couple weeks http://www.shinners.org/pete/NumPy17_20.zip this is numeric-17.0, compiled for 2.0beta btw, much thanks and congrats to the numpy team. getting this compiled and installed was WORLDS better than working with the 16.x releases. thanks! (and congrats!)

2 1

How Can I find out if an array is Contiguous in an extension module?
by Chris Barker Sept. 29, 2000

Sept. 29, 2000

Hi all, I'm writing an extension module that uses PyArrayObjects, and I want to be able to tell if an array passed in is contiguous. I know that I can use PyArray_ContiguousFromObject, and it will just return a reference to the same array if it is contiguous, but I want to know whether or not a new array has been created. I realize that most of the time it doesn't matter, but in this case I am chaning the array in place, and need to pass it to another function that is expecting a standard C array, so I need to make sure the user has passed in a contiguous array. I was surprised to not find a "PyArray_Contiguous" function, or something like it. I see that there is a field in PyArrayObject (int flags) that has a bit indicating whether a field is contiguous, but being a newbe to C as well, I'm not sure how to get at it. I'd love a handy utility function, but if one doesn't exist, can someone send me the code I need to check that bit? thanks, -Chris -- Christopher Barker, Ph.D. cbarker(a)jps.net --- --- --- http://www.jps.net/cbarker -----@@ -----@@ -----@@ ------@@@ ------@@@ ------@@@ Water Resources Engineering ------ @ ------ @ ------ @ Coastal and Fluvial Hydrodynamics ------- --------- -------- ------------------------------------------------------------------------ ------------------------------------------------------------------------

2 1

Numeric-17.0.tar.gz released
by Paul F. Dubois Sept. 22, 2000

Sept. 22, 2000

I have released the current CVS image as 17.0. The tag is r17_0.

1 0

rich comparisons
by Greg Ball Sept. 21, 2000

Sept. 21, 2000

> Can anyone comment on what's happening with arrays of booleans in Numpy? > I don't want to duplicate someone elses effort, but don't mind standing > on someone elses shoulders. My application calls for operations on both > non-sparse and sparce matrices. "Rich comparisons" are really only syntactic sugar. For non-sparse matrices the ufuncs greater(a,b) and less(a,b) will do the job. Equivalents for sparse matrices probably exist. -Greg Ball

1 0

Question: arrays of booleans
by trainor＠uic.edu Sept. 20, 2000

Sept. 20, 2000

Hello -- I'm a Numpy Newbie. I have a question for the Numpy gurus about comparisons of multiarray objects and arrays of booleans in particular. Back when I was checking out Numpy for an application, I read a note in the Ascher/Dubois/Hinsen/Hugunin/Oliphant manual about comparisons of multiarray objects. It said and still says: "Currently, comparisons of multiarray objects results in exceptions, since reasonable results (arrays of booleans) are not doable without non-trivial changes to the Python core. These changes are planned for Python 1.6, at which point array object comparisons will be updated." ( http://numpy.sourceforge.net/numdoc/HTML/numdoc.html ) Can anyone comment on what's happening with arrays of booleans in Numpy? I don't want to duplicate someone elses effort, but don't mind standing on someone elses shoulders. My application calls for operations on both non-sparse and sparce matrices. douglas

2 1

can i improve this code?
by Pete Shinners Sept. 19, 2000

Sept. 19, 2000

I have image data stored in a 3D array. the code is pretty simple, but what i don't like about it is needing to transpose the array twice. here's the code... def map_rgb_array(surf, a): "returns an array of 2d mapped pixels from a 3d array" #image info needed to convert map rgb data loss = surf.get_losses[:3] shift = surf.get_shifts()[:3] prep = a >> loss << shift return transpose(bitwise_or.reduce(transpose(prep))) once i get to the 'prep' line, my 3d image has all the values for R,G,B mapped to the appropriate bitspace. all i need to do is bitwise_or the values together "finalcolor = R|G|B". this is where my lack of guru-ness with numpy comes in. the only way i could figure to do this was transpose the array and then apply the bitwise_or. only problem is then i need to de-transpose the array to get it back to where i started. is there some form or mix of bitwise_or i can use to make it operate on the 3rd axis instead of the 1st? thanks all, hopefully this can be improved. legibility comes second to speed as a priority :] ... hmm, tinkering time passes ... i did find this, "prep[:,:,0] | prep[:,:,1] | prep[:,:,2]". is something like that going to be best? "bitwise_or.reduce((prep[:,:,0], prep[:,:,1], prep[:,:,2]))"

1 0

[ANNOUNCE] HappyDoc docs added to numpy site
by Paul F. Dubois Sept. 19, 2000

Sept. 19, 2000

Check it out at http://numpy.sourceforge.net/doc

1 0

Building Numpy under Python 1.6, Windows
by Jonathan M. Gilligan Sept. 19, 2000

Sept. 19, 2000

I have recently upgraded to Python 1.6 (final). Now I can't figure out how to build Numpy with lapack_lite under windows. There is not a makefile for lapack_lite for MSVC and the instructions in README don't really help. All that setup.py will do is complain that lapack_lite is not installed. Specifically, are there specific compiler flags that I need to use to compile lapack lite? Should I just emulate the unix version and do cl -c *.c lib -out:blas.lib blas_lite.obj lib -out:lapack.lib dlapack_lite.obj f2c_lite.obj zlapack_lite.obj I tried doing this, but when I try to run the NumTut examples, I get the following error: D:\Programming\python\Numerical\Demo>python Python 1.6 (#0, Sep 5 2000, 08:16:13) [MSC 32 bit (Intel)] on win32 Copyright (c) 1995-2000 Corporation for National Research Initiatives. All Rights Reserved. Copyright (c) 1991-1995 Stichting Mathematisch Centrum, Amsterdam. All Rights Reserved. >>> import NumTut Traceback (most recent call last): File "<stdin>", line 1, in ? File "NumTut\__init__.py", line 14, in ? greece = pickle.load(open(os.path.join(_dir, 'greece.pik'), 'rb')) / 256.0 File "D:\Programming\python\Python 1.6\lib\pickle.py", line 855, in load return Unpickler(file).load() File "D:\Programming\python\Python 1.6\lib\pickle.py", line 515, in load dispatch[key](self) File "D:\Programming\python\Python 1.6\lib\pickle.py", line 688, in load_globa l klass = self.find_class(module, name) File "D:\Programming\python\Python 1.6\lib\pickle.py", line 698, in find_class raise SystemError, \ from module Numericto import class array_constructor >>> FWIW, I am using the versions from :pserver:anonymous@cvs.numpy.sourceforge.net:/cvsroot/numpy, module Numerical, checked out as of Sept. 14. I didn't see any tags defined in the repository corresponding to release 16.x. Did I miss something? Should the releases not be getting tagged in the CVS repository? Thanks for any pointers, Jonathan

2 3

Re: New put function
by Travis Oliphant Sept. 18, 2000

Sept. 18, 2000

Paul, Great job on the new put function. I can't wait to try it out. This goes a long way towards eliminating one of the few complaints I've heard about Numerical Python when compared to other similar environments. -Travis

1 0