Mailman 3 November 2007 - SciPy-User

openmp and weave?
by william ratcliff 07 Nov '07

07 Nov '07

Has anyone had any luck using weave with openMP? If so, what did you have to do? I've started by updating my compiler to MinGW: gcc-4.2.1-dw-2-2 (and similarly for g++), but am running into problems with code written in weave that doesn't use any of openmp: Here is the code: import numpy as N import weave from weave import converters def blitz_interpolate(x,y): code = """ int pts = Ny[0]; //#pragma omp parallel for for (int i=0; i < pts-1; i++){ y(i) = sin( exp( cos( - exp( sin(x(i)) ) ) ) ); } return_val = 3; """ extra=["-fopenmp -Lc:/python25/ -lPthreadGC2"] extra=[] z=weave.inline(code,['x','y'],type_converters=converters.blitz,compiler='gcc') print z return if __name__=="__main__": x=N.arange(1000) y=N.zeros(x.shape,'d') blitz_interpolate(x,y) print x[35], y[35],N.sin(N.exp(N.cos(-N.exp(N.sin(x[35]))))) This works fine with version 3.4.2 of gcc, g++ Thanks, William

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Is this a bug: scipy.cov([0,1]) = 0
by Emin.shopper Martinian.shopper 07 Nov '07

07 Nov '07

Dear Experts, I recently noticed some strange behavior with scipy (and numpy as well). Doing scipy.cov([0,1]) returns 0 which I believe is incorrect. Doing scipy.cov([0.0,1.0]) returns a more reasonable answer so I suspect that the problem is that scipy is using integer math. Is this considered a bug? I can see no good reason to do integer math when computing a covariance. Thanks, -Emin

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Is Elefant alive ?
by Stef Mientki 07 Nov '07

07 Nov '07

hello, Does anyone knows how I can reach one of the Elefant designers: http://elefant.developer.nicta.com.au/ I've spitted through all their mailinglists ;-) but couldn't find an address. I also subscribed to their mailing lists, but didn't hear anything for 2 days ;-) thanks, Stef Mientki

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Re: [SciPy-user] HDF5 Viewer for Python
by Clowers, Brian H 07 Nov '07

07 Nov '07

Gael, Thanks for the input. A while back I dabbled with Traits and look at your tutorial--thanks by the way. However, I was unsure how to use traits to develop some sort of Treeview for the HDF5 format. Which leads me to beg for your help...I'm sure your 'ugly' code is better than mine on just about any given day. If you'd be willing to share--even if it is to get me started I'd appreciate your help. The enthought packed looks very promising so now might be a good time for me to take it up. I upgraded my system to use the latest version of traits (I believe it is 3) but am unsure how to begin populating a tree. Any examples would be great. Thanks Brian

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HDF5 Viewer for Python
by Clowers, Brian H 07 Nov '07

07 Nov '07

I have data sets in a HDF5 format that contain a number of arrays which I'd like to plot using matplotlib. I can do this pretty easily using just IDLE and pyTables, however, it would be nice to put together a GUI and automate some of the key strokes. Does anyone know of or have an alternative to viTables that they'd be willing to share? viTables looks great but it is also 250 Euros for single license--then again if it had the capability to directly plot to matplotlib I'd consider it. Anyway, when it comes to a GUI I imagine the challenge would be how to link the arrays or tables in the HDF5 file to a Treeview in an interactive manner. Any thoughts? Thanks, Brian

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Element ranks for an array
by R. Padraic Springuel 07 Nov '07

07 Nov '07

Does scipy have a function that can provide the element ranks by size for a 1-d array? I.e. a function that would return [3,4,2,1] or [2,1,3,4] (depending on ascending or descending ranking) for array([50, 10, 62, 1000]). -- R. Padraic Springuel Teaching Assistant Department of Physics and Astronomy University of Maine Bennett 309 Office Hours: By appointment only

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gaussian smoothing
by Marc Beck 06 Nov '07

06 Nov '07

I am a graduate assistant at the Space Science Center at Morehead State University. I am currently writing a program to convert raw data from our 21m antenna into a *.FITS image using numpy and scipy. I need to convolve the pixels of my image. I have three arrays: one for the x- coordinate, one for the y- coordinate and one for the brightness of the pixel. I need to feed those three arrays into a function to convolve the pixels and I need to get the same three arrays out with the new values, or the rest of the program does not work. Someone from the python forum referred me to some code at http://www.scipy.org/Cookbook/SignalSmooth but I don't understand which variable is what and how to integrate this into my program. Please explain to me how I can make my program work. I hope that I have described clearly enough what I am planning to do. I e-mailed the author of that code and asked for help, but this person is very busy and does not have the time to help me. Marc Beck __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Assessing the use of packages
by Pierre GM 06 Nov '07

06 Nov '07

All, It's evaluation time in my department (Bio. & Ag. Engng, UGA), and I'd need to document the impact of my Python contributions on the scientific community at large, or more realistically on the numpy/scipy user community... * Is there a way to estimate how many people installed one particular package from the SVN ? * if it's too tricky, would anybody using maskedarray and/or timeseries and/or pyloess (the SVN packages I helped implementing) mind dropping me a line off-list, with a very short description of the main field of research/use ? I'd basically need some kind of numbers to give to the People-In-Charge. Thanks a lot in advance for your time. P. PS: Sorry for the cross-posting..

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Scipy + Vision = LabView ?
by Stef Mientki 06 Nov '07

06 Nov '07

hello, I found this demo (5 min) of Vision today http://www.osc.edu/~unpingco/Tutorial1.html If we combine this with Scipy, we've an almost complete replacement of LabView. Or am I dreaming ? cheers, Stef Mientki

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weave and masked arrays?
by william ratcliff 05 Nov '07

05 Nov '07

Does anyone know if scipy.weave supports numpy masked arrays? Thanks, William

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