Mailman 3 December 2015 - NumPy-Discussion

Numpy 1.10.2rc2 released
by Charles R Harris Dec. 9, 2015

Dec. 9, 2015

Hi All, I'm pleased to announce the release of Numpy 1.10.2rc2. After two months of stomping bugs I think the house is clean and we are almost ready to put it up for sale. However, bugs are persistent and may show up at anytime, so please inspect and test thoroughly. Windows binaries and source releases can be found at the usual place on Sourceforge <https://sourceforge.net/projects/numpy/files/NumPy/1.10.2rc2/>. If there are no reports of problems in the next week I plan to release the … [View More]

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Memory mapping and NPZ files
by Mathieu Dubois Dec. 9, 2015

Dec. 9, 2015

Dear all, If I am correct, using mmap_mode with Npz files has no effect i.e.: f = np.load("data.npz", mmap_mode="r") X = f['X'] will load all the data in memory. Can somebody confirm that? If I'm correct, the mmap_mode argument could be passed to the NpzFile class which could in turn perform the correct operation. One way to handle that would be to use the ZipFile.extract method to write the Npy file on disk and then load it with numpy.load with the mmap_mode argument. Note that the user … [View More]

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array of random numbers fails to construct
by DAVID SAROFF (RIT Student) Dec. 8, 2015

Dec. 8, 2015

This works. A big array of eight bit random numbers is constructed: import numpy as np spectrumArray = np.random.randint(0,255, (2**20,2**12)).astype(np.uint8) This fails. It eats up all 64GBy of RAM: spectrumArray = np.random.randint(0,255, (2**21,2**12)).astype(np.uint8) The difference is a factor of two, 2**21 rather than 2**20, for the extent of the first axis. -- David P. Saroff Rochester Institute of Technology 54 Lomb Memorial Dr, Rochester, NY 14623 david.saroff(a)mail.rit.edu | (434) 227-6242

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Re: [Numpy-discussion] Q: Use of scipy.signal.bilinear
by R Schumacher Dec. 8, 2015

Dec. 8, 2015

Sorry - I'll join there. - Ray At 10:00 AM 12/8/2015, you wrote: >On Tue, Dec 8, 2015 at 9:30 AM, R Schumacher ><<mailto:rays@blue-cove.com>rays(a)blue-cove.com> wrote: >We have a function which describes a frequency >response correction to piezo devices we use. To >flatten the FFT, it is similar to: >Cdis_t = .5 >N = 8192 >for n in range(8192): >Â B3 = n * 2560 / N >Â Fc(n) = 1 / >((B3/((1/(Cdis_t*2*pi))**2+B3**2)**0.5)*(-0.01*log(B3) + 1.… [View More]

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Q: Use of scipy.signal.bilinear
by R Schumacher Dec. 8, 2015

Dec. 8, 2015

We have a function which describes a frequency response correction to piezo devices we use. To flatten the FFT, it is similar to: Cdis_t = .5 N = 8192 for n in range(8192): B3 = n * 2560 / N Fc(n) = 1 / ((B3/((1/(Cdis_t*2*pi))**2+B3**2)**0.5)*(-0.01*log(B3) + 1.04145)) In practice it really only matters for low frequencies. I suggested that we might be able to do a time domain correction as a forward-reverse FFT filter using the function, but another said it can also be applied in … [View More]

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Re: [Numpy-discussion] Where is Jaime?
by Peter Creasey Dec. 8, 2015

Dec. 8, 2015

>> > >> > Is the interp fix in the google pipeline or do we need a workaround? >> > >> >> Oooh, if someone is looking at changing interp, is there any chance >> that fp could be extended to take complex128 rather than just float >> values? I.e. so that I could write: >> >> >>> y = interp(mu, theta, m) >> rather than >> >>> y = interp(mu, theta, m.real) + 1.0j*interp(mu, theta, m.imag) >> >> … [View More]

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Where is Jaime?
by Charles R Harris Dec. 7, 2015

Dec. 7, 2015

Anyone hear from Jaime lately? He seems to have gone missing. Chuck

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Re: [Numpy-discussion] NumPy-Discussion Digest, Vol 111, Issue 9
by Sydney Shall Dec. 7, 2015

Dec. 7, 2015

On 07/12/2015 09:38, numpy-discussion-request(a)scipy.org wrote: > Message: 4 > Date: Sun, 06 Dec 2015 22:01:40 -0500 > From: "DAVID SAROFF (RIT Student)"<dps7802(a)rit.edu> > To: Discussion of Numerical Python<numpy-discussion(a)scipy.org> > Cc: Stefi Baum<stefibaumodea(a)gmail.com> > Subject: Re: [Numpy-discussion] array of random numbers fails to > construct > Message-ID: > <CABMftcSkX9kL=G2sepOn80YCKQygFGHa7WBdmAxy3_1iVAtJcw(a)mail.gmail.com… [View More]

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Re: [Numpy-discussion] Where is Jaime?
by Peter Creasey Dec. 6, 2015

Dec. 6, 2015

> > Is the interp fix in the google pipeline or do we need a workaround? > Oooh, if someone is looking at changing interp, is there any chance that fp could be extended to take complex128 rather than just float values? I.e. so that I could write: >>> y = interp(mu, theta, m) rather than >>> y = interp(mu, theta, m.real) + 1.0j*interp(mu, theta, m.imag) which *sounds* like it might be simple and more (Num)pythonic. Peter

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Travis is busted.
by Charles R Harris Dec. 5, 2015

Dec. 5, 2015

Just to note that travis is broken at the moment, it can't find the whitelisted gfortran package.

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f2py, numpy.distutils and multiple Fortran source files
by David Verelst Dec. 5, 2015

Dec. 5, 2015

Hi, For the wafo [1] package we are trying to include the extension compilation process in setup.py [2] by using setuptools and numpy.distutils [3]. Some of the extensions have one Fortran interface source file, but it depends on several other Fortran sources (modules). The manual compilation process would go as follows: gfortran -fPIC -c source_01.f gfortran -fPIC -c source_02.f f2py -m module_name -c source_01.o source_02.o source_interface.f Can this workflow be incorporated into … [View More]

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NumPy Pyston support
by Boxiang Sun Dec. 5, 2015

Dec. 5, 2015

Hi all, I am an open source contributor of Pyston, and working on NumPy Pyston support(Pyston: https://github.com/dropbox/pyston) I disabled some tests which cause segfaults. This is current situation(in my local branch): ---------------------------------- Ran 3240 tests in 80.811s FAILED (KNOWNFAIL=3, SKIP=6, errors=334, failures=74) ---------------------------------- Indeed, the time consuming was longer than CPython. I think this is because of the additional exceptions / frame … [View More]

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future of f2py and Fortran90+
by Eric Firing Dec. 4, 2015

Dec. 4, 2015

F2py is a great tool, but my impression is that it is being left behind by the evolution of Fortran from F90 onward. This is unfortunate; it would be nice to be able to easily wrap new Fortran libraries. I'm curious: has anyone been looking into what it would take to enable f2py to handle modern Fortran in general? And into prospects for getting such an effort funded? Eric

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Recognizing a cycle in a vector
by Manolo Martínez Dec. 3, 2015

Dec. 3, 2015

Dear all, Suppose that I have a vector with the numerical solution of a differential equation -- more concretely, I am working with evolutionary game theory models, and the solutions are frequencies of types in a population that follows the replicator dynamics; but this is probably irrelevant. Sometimes these solutions are cyclical, yet I sample at points which do not correspond with the period of the cycle, so that np.allclose() cannot be directly applied. Is there any way to check for … [View More]

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ANN: SciExp^2 (1.1.2)
by Lluís Vilanova Dec. 2, 2015

Dec. 2, 2015

Hi all! I'm really happy to make the first public announcement of SciExp^2 (actually, it's release 1.1.2). Home page: https://projects.gso.ac.upc.edu/projects/sciexp2 Description ----------- SciExp² (aka SciExp square or simply SciExp2) stands for Scientific Experiment Exploration, which contains a comprehensive framework for easing the workflow of creating, executing and evaluating experiments. The driving idea behind SciExp² is the need for quick and effortless design-space exploration. … [View More]

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Indexing structured masked arrays with multidimensional fields; what with fill_value?
by Gerrit Holl Dec. 1, 2015

Dec. 1, 2015

Hello, usually, a masked array's .fill_value attribute has ndim=0 and the same dtype as the data attribute: In [27]: ar = array((0, [[0.0, 0.0, 0.0], [0.0, 0.0, 0.0]], 0.0), dtype="int, (2,3)float, float") In [28]: arm = ma.masked_array(ar) In [29]: arm.fill_value.ndim Out[29]: 0 In [31]: arm.fill_value.dtype Out[31]: dtype([('f0', '<i8'), ('f1', '<f8', (2, 3)), ('f2', '<f8')]) What would be the optimal approach for .fill_value if I address the member "f1" in this case? The … [View More]

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ANN: SfePy 2015.4
by Robert Cimrman Dec. 1, 2015

Dec. 1, 2015

I am pleased to announce release 2015.4 of SfePy. Description ----------- SfePy (simple finite elements in Python) is a software for solving systems of coupled partial differential equations by the finite element method or by the isogeometric analysis (preliminary support). It is distributed under the new BSD license. Home page: http://sfepy.org Mailing list: http://groups.google.com/group/sfepy-devel Git (source) repository, issue tracker, wiki: http://github.com/sfepy Highlights of this … [View More]

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Inconsistent/unexpected indexing semantics
by Lluís Vilanova Nov. 30, 2015

Nov. 30, 2015

Hi, TL;DR: There's a pending pull request deprecating some behaviour I find unexpected. Does anyone object? Some time ago I noticed that numpy yields unexpected results in some very specific cases. An array can be used to index multiple elements of a single dimension: >>> a = np.arange(8).reshape((2,2,2)) >>> a[ np.array([[0], [0]]) ] array([[[[0, 1], [2, 3]]], [[[0, 1], [2, 3]]]]) Nonetheless, if a list is used … [View More]

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