NumPy-Discussion December 2007

numpy-discussion@python.org

77 participants
75 discussions

Re: [Numpy-discussion] display numpy array as image
by Joe Harrington 03 Dec '07

03 Dec '07

If you want to explore the array interactively, blink images, mess with colormaps using the mouse, rescale the image values, mark regions, add labels, look at dynamic plots of rows and columns, etc., get the ds9 image viewer and the xpa programs that come with it that allow it to communicate with other programs: ftp://sao-ftp.harvard.edu/pub/rd/ds9 http://hea-www.harvard.edu/RD/ds9/index.html Then get the Python numdisplay package, which uses xpa. You have to get numdisplay from inside the stsci_python package: http://www.stsci.edu/resources/software_hardware/pyraf/stsci_python/current… Just grab the numdisplay directory from within that. Older versions of numdisplay are standalone but don't work perfectly. Beware, there are outdated web sites about numdisplay on the stsci site. Don't google! Run ds9 before you load numdisplay. Then you can send your python arrays to a real interactive data viewer at will. There are even mechanisms to define physical coordinates mapped from the image coordinates. --jh--

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python-numpy debian package and f2py
by Ondrej Certik 03 Dec '07

03 Dec '07

Hi, I am a comaintainer of the python-scipy package in Debian and now it seems to be in quite a good shape. However, the python-numpy package is quite a mess, so as it usually goes in opensource, I got fedup and I tried to clean it. But I noticed, that f2py was moved from external package into numpy, however the versions mishmatch: The newest (deprecated) python-f2py package in Debian has a version 2.45.241+1926, so I assume this was the version of f2py, before merging with numpy. However, the f2py in numpy says when executing: Version: 2_3816 numpy Version: 1.0.3 so I assume the version of f2py in numpy is 2_3816? So has the versioning scheme of f2py changed? Another question - since both numpy and f2py is now built from the same source, doesn't f2py simply has the same version as numpy, i.e. 1.0.3? Note: I know there is a newer numpy release, but that's not the point now. I am asking because we probably will have to remove the old python-f2py package and build a new one from the sources of numpy, etc., and it will take some time until this happens (ftpmasters need to remove the old package from the archive, then the new binary package needs to go to the NEW queue for approval etc.), so I would like to make sure I understand the versioning and the future plans with numpy and f2py, before starting the transition in Debian. Actually, does it even make sense to create a python-f2py package? It seems so (to me), it's a separate program. But since you decided to merge it with numpy, what are your thoughts about it? Thanks a lot, Ondrej

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random.hypergeometric bug
by Chris 03 Dec '07

03 Dec '07

There appears to be a bug in numpy's hypergeometric random number generator. Here is an example -- if I generate 1000 hg samples with 4 draws from a space with 30 successes and 10 failures: In [39]: x = hg(30, 10, 4, 1000) I should get a mean value of: In [40]: 4*30./40 Out[40]: 3.0 But the sample mean is way to small: In [41]: mean(x) Out[41]: 0.996

2 1

swig numpy2carray converters
by Georg Holzmann 01 Dec '07

01 Dec '07

Hallo! Because I had some troubles in wrapping my C++ library in python/numpy, I did (another) numpy2carray.i file for SWIG. With that interface file it is possible to input/output arrays with or without copying data (I also included an example for an interface to fortran style arrays). I am still a numpy newbie, so this might not be perferct, but however, I finally found some time to put it online - maybe it is helpfull for other beginners: http://grh.mur.at/software/numpy2carray.html LG Georg

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Re: [Numpy-discussion] display numpy array as image (Giorgio F. Gilestro)
by Joe Harrington 01 Dec '07

01 Dec '07

I was misinformed about the status of numdisplay's pages. The package is available as both part of stsci_python and independently, and its (up-to-date) home page is here: http://stsdas.stsci.edu/numdisplay/ Googling numdisplay finds that page. My apologies to those inconvenienced by my prior post. Note that there is practical documentation and examples of how to use it for astronomical image display in the Data Analysis Tutorial: http://www.scipy.org/wikis/topical_software/Tutorial --jh--

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NumPy-Discussion December 2007