Mailman 3 March 2015 - NumPy-Discussion

Re: [Numpy-discussion] Asking proposal review/feedback for GSOC 15
by Oğuzhan Ünlü 24 Mar '15

24 Mar '15

Hi Nikolay, Thanks for pointing out that! It really helped. I think it looks better and easier to review now. I appreciate any comment/feedback. My proposal is at https://gist.github.com/oguzhanunlu/1f8bf3ffc6ac5c420dd1 Thanks in advance, Oguzhan Hi, Oguzhan. I suggest to add .md extension to the gist file, now it is > displayed as raw text. >

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Vector math library integration
by Орипов Акбар 24 Mar '15

24 Mar '15

Hello! I want to contribute to NumPy/SciPy, namely I am interested in project Vector math library integration. I have good skills of C and Python, so I can make it. Please, send me additional information about this idea asap. Have a nice day! Best regards, Akbar IRC: aki93 at freenode dot net

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netcdf lat lon to coord - ValueError: need more than 1 value to unpack
by questions anon 24 Mar '15

24 Mar '15

I would like to find the nearest coord in a netcdf from a given latitude and longitude. I found some fantastic code that does this - http://nbviewer.ipython.org/github/Unidata/unidata-python-workshop/blob/mas… but I keep receiving this error - I am receiving a ValueError: need more than 1 value to unpack I have pasted the code and full error below. Any help will be greatly appreciated. import numpy as np import netCDF4 def naive_fast(latvar,lonvar,lat0,lon0): # Read latitude and longitude from file into numpy arrays latvals = latvar[:] lonvals = lonvar[:] ny,nx = latvals.shape dist_sq = (latvals-lat0)**2 + (lonvals-lon0)**2 minindex_flattened = dist_sq.argmin() # 1D index of min element iy_min,ix_min = np.unravel_index(minindex_flattened, latvals.shape) return iy_min,ix_min filename = "/Users/T_SFC.nc" ncfile = netCDF4.Dataset(filename, 'r') latvar = ncfile.variables['latitude'] lonvar = ncfile.variables['longitude'] iy,ix = naive_fast(latvar, lonvar, -38.009, 146.438) print 'Closest lat lon:', latvar[iy,ix], lonvar[iy,ix] ncfile.close() --------------------------------------------------------------------------- ValueError Traceback (most recent call last) /Applications/Canopy.app/appdata/canopy-1.3.0.1715.macosx-x86_64/Canopy.app/Contents/lib/python2.7/site-packages/IPython/utils/py3compat.pyc in execfile(fname, *where) 202 else: 203 filename = fname --> 204 __builtin__.execfile(filename, *where) /Users/latlon_to_closestgrid.py in <module>() 22 lonvar = ncfile.variables['longitude'] 23 ---> 24 iy,ix = naive_fast(latvar, lonvar, -38.009, 146.438) 25 print 'Closest lat lon:', latvar[iy,ix], lonvar[iy,ix] 26 ncfile.close() /Users/latlon_to_closestgrid.py in naive_fast(latvar, lonvar, lat0, lon0) 12 latvals = latvar[:] 13 lonvals = lonvar[:] ---> 14 ny,nx = latvals.shape 15 dist_sq = (latvals-lat0)**2 + (lonvals-lon0)**2 16 minindex_flattened = dist_sq.argmin() # 1D index of min element ValueError: need more than 1 value to unpack

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Hang in numpy.zeros
by Albert Zeyer 24 Mar '15

24 Mar '15

Hi, I have a multithreaded multiprocessing Python 2.7 project with Theano. In my main proc, I recognized a hang in numpy.zeros. It deadlocks with the Python GIL and other native threads will lock on the Python GIL. I found a somewhat related problem described here about such a deadlock in numpy.dot: http://stackoverflow.com/questions/23963997/python-child-process-crashes-on… I have Numpy 1.9.1 on Ubuntu 12.04. How can I fix this? Is this a known problem? Kind Regards, Albert

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EuroScipy 2015: Call for talks, posters & tutorials
by Nicolas P. Rougier 24 Mar '15

24 Mar '15

Dear all, EuroScipy 2015, the annual conference on Python in science will take place in Cambridge, UK on 26-30 August 2015. The conference features two days of tutorials followed by two days of scientific talks & posters and an extra day dedicated to developer sprints. It is the major event in Europe in the field of technical/scientific computing within the Python ecosystem. Data scientists, analysts, quants, PhD's, scientists and students from more than 20 countries attended the conference last year. The topics presented at EuroSciPy are very diverse, with a focus on advanced software engineering and original uses of Python and its scientific libraries, either in theoretical or experimental research, from both academia and the industry. Submissions for posters, talks & tutorials (beginner and advanced) are welcome on our website at http://www.euroscipy.org/2015/ <http://www.euroscipy.org/2015/> Sprint proposals should be addressed directly to the organisation at euroscipy-org(a)python.org <mailto:euroscipy-org@python.org?subject=Sprint%20proposal> Important dates Mar 24, 2015 Call for talks, posters & tutorials Apr 30, 2015 Talk and tutorials submission deadline May 1, 2015 Registration opens May 30, 2015 Final program announced Jun 15, 2015 Early-bird registration ends Aug 26-27, 2015 Tutorials Aug 28-29, 2015 Main conference Aug 30, 2015 Sprints We look forward to an exciting conference and hope to see you in Cambridge The EuroSciPy 2015 Team - http://www.euroscipy.org/2015/ <http://www.euroscipy.org/2015/>

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Introductory mail and GSoc Project "Vector math library integration"
by Dp Docs 24 Mar '15

24 Mar '15

Hi all, I am a CS 3rd Undergrad. Student from an Indian Institute (III T). I believe I am good in Programming languages like C/C++, Python as I have already done Some Projects using these language as a part of my academics. I really like Coding (Competitive as well as development). I really want to get involved in Numpy Development Project and want to take "Vector math library integration" as a part of my project. I want to here any idea from your side for this project. Thanks For your time for reading this email and responding back. My IRCnickname: dp Real Name: Durgesh Pandey.

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Re: [Numpy-discussion] Asking proposal review/feedback for GSOC 15
by Oğuzhan Ünlü 24 Mar '15

24 Mar '15

Hi again, Thanks Ralf, I understand that. Then, I would like to share a public link to my proposal and I appreciate anybody who take time and leave comment/give feedback. It is on Github Gist. URL: https://gist.github.com/oguzhanunlu/1f8bf3ffc6ac5c420dd1 Thanks in advance, Oguzhan > Hi, > > > > My name is O?uzhan(You may use 'Oguzhan'). I submitted a proposal on the > > system with the title 'NumPy - Vector math library integration'. Ralf > > commented on my proposal and advised to ask for a feedback on mailing > list > > and here I am. > > > > I would appreciate any feedback from community. I think community members > > are able to view my proposal, its visibility is set to 'Organization > > members'. > > > > I preferred my name in its original form, if any mentor would like to > > search, I provide my name on system below. > > Name: O?uzhan ?nl? > > > > Hi O?uzhan, > > There are only a handful of potential mentors signed up in Melange, and > this list is read by hundreds of people. So it would be good to post your > proposal in a publicly accessible place and post the link here. Good > options are on Github or on StackEdit. > > Cheers, > Ralf > > P.S. for those who do have access to Melange: > > http://www.google-melange.com/gsoc/proposal/review/org/google/gsoc2015/blac… >

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numpy.i: passing in in-place ND array as "flat" 1D array
by Tom Krauss 23 Mar '15

23 Mar '15

I have a method on a C++ object that treats all elements the same and modifies the array in-place (quantizes each value). Usually I just have a vector, i.e. a 1D array. But today I wanted to quantize a 2D array, and the (DATA_TYPE* INPLACE_ARRAY1, DIM_TYPE DIM1) failed to do the trick, because of the require_dimensions(array, 1) call. So I created a new typemap in numpy.i (DATA_TYPE* INPLACE_ARRAY_FLAT, DIM_TYPE DIM_FLAT) that omits the call to "require_dimensions", and behold! It works for both 1D and 2D (and really any D). Does this seem like a reasonable addition to numpy.i? Or is there another way to do this that I am missing? Regards, Tom

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Rewrite np.histogram in c?
by Robert McGibbon 23 Mar '15

23 Mar '15

Hi, Numpy.histogram is implemented in python, and is a little sluggish. This has been discussed previously on the mailing list, [1, 2]. It came up in a project that I maintain, where a new feature is bottlenecked by numpy.histogram, and one developer suggested a faster implementation in cython [3]. Would it make sense to reimplement this function in c? or cython? Is moving functions like this from python to c to improve performance within the scope of the development roadmap for numpy? I started implementing this a little bit in c, [4] but I figured I should check in here first. -Robert [1] http://scipy-user.10969.n7.nabble.com/numpy-histogram-is-slow-td17208.html [2] http://numpy-discussion.10968.n7.nabble.com/Fast-histogram-td9359.html [3] https://github.com/mdtraj/mdtraj/pull/734 [4] https://github.com/rmcgibbo/numpy/tree/histogram

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Asking proposal review/feedback for GSOC 15
by Oğuzhan Ünlü 23 Mar '15

23 Mar '15

Hi, My name is Oğuzhan(You may use 'Oguzhan'). I submitted a proposal on the system with the title 'NumPy - Vector math library integration'. Ralf commented on my proposal and advised to ask for a feedback on mailing list and here I am. I would appreciate any feedback from community. I think community members are able to view my proposal, its visibility is set to 'Organization members'. I preferred my name in its original form, if any mentor would like to search, I provide my name on system below. Name: Oğuzhan Ünlü Thanks in advance,

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