Mailman 3 February 2008 - NumPy-Discussion

Re: [Numpy-discussion] Numpy and C++ integration...
by Glen W. Mabey Feb. 6, 2008

Feb. 6, 2008

On Wed, Feb 06, 2008 at 03:23:43AM -0600, Kent-Andre Mardal wrote: > No problem, it is now under BSD. OK? Perfect. Thank you. Glen

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Numpy and C++ integration...
by Vince Fulco Feb. 6, 2008

Feb. 6, 2008

Dear Numpy Experts- I find myself working with Numpy arrays and wanting to access *simple* C++ functions for time series returning the results to Numpy. As I am a relatively new user of Python/Numpy, the number of paths to use in incorporating C++ code into one's scripts is daunting. I've attempted the Weave app but can not get past the examples. I've also looked at all the other choices out there such as Boost, SIP, PyInline, etc. Any trailheads for the simplest approach (assuming a very minimal understanding of C++) would be much appreciated. At this point, I can't release the code however for review. Thank you. -- Vince Fulco

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[ANN] Blas-LAPACK superpack, 2nd alpha
by David Cournapeau Feb. 6, 2008

Feb. 6, 2008

Hi, I have finished a second alpha of the BLAS/LAPACK superpack for windows: http://www.ar.media.kyoto-u.ac.jp/members/david/archives/blas-lapack-superp… (~ 9 Mb). Changes from first alpha - Both SSE3 and SSE2 are supported. - custom installation possible: you can choose to install .a, .dll, .def and .lib for any target, atlas or netlib. The super pack is an installer which by default install the most optimized blas/lapack possible to compile numpy/scipy with. cheers, David

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[Bug] important bug in method sum
by humufr＠yahoo.fr Feb. 6, 2008

Feb. 6, 2008

Hello, when doing some test I saw a very important bug in numpy (at least on the svn version and 1.0.3 (ubuntu package)). I'm using a svn version of numpy: In [31]: numpy.__version__ Out[31]: '1.0.5.dev4767' The problem is for an array larger than 256*256 the sum is going crazy. In [45]: numpy.arange(256*256) Out[45]: array([ 0, 1, 2, ..., 65533, 65534, 65535]) In [46]: numpy.arange(256*256).sum() Out[46]: 2147450880 In [47]: numpy.arange(257*257) Out[47]: array([ 0, 1, 2, ..., 66046, 66047, 66048]) In [48]: numpy.arange(257*257).sum() Out[48]: -2113765120 >>> import numpy >>> numpy.arange(256*256).sum() 2147450880 >>> numpy.arange(257*257).sum() -2113765120 >>> numpy.__version__ '1.0.3' Sorry for this bad news. N. ps: my system is an ubuntu linux 32

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Stride of 2 for correlate()
by Chris Finley Feb. 6, 2008

Feb. 6, 2008

Greetings, After searching the archives, I was unable to find a good method for changing the stride of the correlate or convolve routines. I am doing a Daubechies analysis of some sample data, say data = arange(0:80). The coefficient array or four floats (say daub_g2[0:4]) is correlated over the data. However, the product only needs to be calculated for every other data index. For example, I need to take the inner product of: data[0:4] with daub_g2[0:4] then data[2:6] with daub_g2[0:4] then data[4:8] with daub_g2[0:4] and so on. You help is greatly appreciated, Chris

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Re: [Numpy-discussion] [Bug] important bug in method sum
by humufr＠yahoo.fr Feb. 5, 2008

Feb. 5, 2008

Sorry its not really a bug. I understood why . It's an integer and I'm doing an overflow. Perhaps an error message can be printed or an automatic change (with a warning) can be done. I think that I prefer to loose the type but keep the value correct. N.

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matrix rank of numpy array or matrix
by mark Feb. 5, 2008

Feb. 5, 2008

Hello - Is there a function to compute the matrix rank of a numpy array or matrix? So I don't mean the current rank(), which gives the number of dimensions. I mean the number of independent equations of a matrix. Thanks, Mark

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Generating a series of integers
by Francesc Altet Feb. 5, 2008

Feb. 5, 2008

Hi, I need to generate a series of uint8 integers similar to: In [37]: numpy.linspace(10, 20, num=25).astype('uint8') Out[37]: array([10, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 15, 16, 16, 17, 17, 17, 18, 18, 19, 19, 20], dtype=uint8) i.e. create evenly spaced samples in a range, but without using an intermediate array to create it (memory footprint is important). I know that I can create this with a loop, but I'm curious if that can be done more compactly in one single sentence. Thanks, -- >0,0< Francesc Altet http://www.carabos.com/ V V Cárabos Coop. V. Enjoy Data "-"

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An idea for future numpy windows installers
by David Cournapeau Feb. 5, 2008

Feb. 5, 2008

Hi, While studying a bit nsis (an open source system to build windows installers), I realized that it would be good if we could detect the target CPU and install the right numpy accordingly. I have coded a nsis plugin to detect SSE availability (no SSE vs SSE vs SSE2 vs SS3), and including installers within the nsis installer is easy. What would people think about including the installers generated with the current method (bdist_wininst, I guess ?) for every CPU target, and distribute the bundled installer ? The only drawback I can see is the size of the installer: in this case, we could have a system which download the right installer, but that would be more work, obviously. This seems like an easy, "not too much work required" solution to the recurrent problem we get with atlas on windows. cheers, David

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round, fix, ceil, and floor for complex args
by Stuart Brorson Feb. 4, 2008

Feb. 4, 2008

Hi -- I'm fiddling with NumPy's chopping and truncating operators: round, fix, ceil, and floor. In the case where they are passed real args, they work just fine. However, I find that when they are passed complex args, I get the following: round -> works fine. ceil -> throws exception: 'complex' object has no attribute 'ceil' floor -> throws exception: 'complex' object has no attribute 'floor' fix -> throws exception: 'complex' object has no attribute 'floor' Please see the session log below for more details. My question: Is this a bug or a feature? It seems to me that if you implement round for complex args, then you need to also support ceil, floor, and fix for complex args, so it's a bug. But I thought I'd ask the developers what they thought before filing a ticket. Regards, Stuart Brorson Interactive Supercomputing, inc. 135 Beaver Street | Waltham | MA | 02452 | USA http://www.interactivesupercomputing.com/ -------------------------- <session log> ------------------- In [14]: import numpy In [15]: A = 10*numpy.random.rand(2, 2) + 10j*numpy.random.rand(2, 2) In [16]: numpy.round(A) Out[16]: array([[ 6.+8.j, 6.+5.j], [ 10.+6.j, 9.+9.j]]) In [17]: numpy.floor(A) --------------------------------------------------------------------------- <type 'exceptions.AttributeError'> Traceback (most recent call last) /fs/home/sdb/<ipython console> in <module>() <type 'exceptions.AttributeError'>: 'complex' object has no attribute 'floor' In [18]: numpy.ceil(A) --------------------------------------------------------------------------- <type 'exceptions.AttributeError'> Traceback (most recent call last) /fs/home/sdb/<ipython console> in <module>() <type 'exceptions.AttributeError'>: 'complex' object has no attribute 'ceil' In [19]: numpy.fix(A) --------------------------------------------------------------------------- <type 'exceptions.AttributeError'> Traceback (most recent call last) /fs/home/sdb/<ipython console> in <module>() /home/sdb/trunk/output/ia32_linux/python/lib/python2.5/site-packages/numpy/lib/ufunclike.py in fix(x, y) 14 x = asanyarray(x) 15 if y is None: ---> 16 y = nx.floor(x) 17 else: 18 nx.floor(x, y) <type 'exceptions.AttributeError'>: 'complex' object has no attribute 'floor' In [20]: numpy.__version__ Out[20]: '1.0.4' In [21]: ---------------------------- </session log> -------------------

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