Mailman 3 March 2018 - SciPy-User

objects with their Delaunay graphs overlaid.
by Franck Kalala March 21, 2018

March 21, 2018

Hello All I am not sure this a good place to ask this. I am just making a try. I have and image and I would like to reproduced the Delaunay graphs overlaid. See the attached image for an idea. I try the following code: from matplotlib import pyplot as plt from skimage.io import imread from skimage.feature import corner_harris, corner_subpix, corner_peaks, peak_local_max from scipy.spatial import Delaunay import matplotlib.pyplot as plt image = imread("cup.png", as_grey='True') #points = corner_peaks(corner_harris(image), min_distance=1) points = peak_local_max(corner_harris(image), min_distance=2) #coords_subpix = corner_subpix(image, coords, window_size=13) tri = Delaunay(points) #imgplot = plt.imshow(image,cmap='gray') #plt.triplot(points[:,0], points[:,1], tri.simplices.copy()) #plt.plot(points[:,0], points[:,1], 'o') #plt.show() #print(image) coords = peak_local_max(corner_harris(image), min_distance=2) coords_subpix = corner_subpix(image, coords, window_size=13) fig, ax = plt.subplots() ax.imshow(image, interpolation='nearest', cmap=plt.cm.gray) ax.plot(coords[:, 1], coords[:, 0], '.b', markersize=3) #ax.plot(coords_subpix[:, 1], coords_subpix[:, 0], '+r', markersize=15) #ax.axis((0, 350, 350, 0)) plt.show() this code does not help. I attach also the cup image for a try. best franck

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Using scipy to fit a bimodal distribution
by spiff007 March 16, 2018

March 16, 2018

Hi Folks, I have some data, which is bimodally distributed. The initial part of the data(in red, in the figure below), seems to be exponentially distributed and the latter part(in blue, in the figure below), seems to be a gamma distribution. See image below (& attached) : What scipy function, i could use to fit this data, knowing that, the first mode is exponential, and the latter, seems to be gamma. If its not possible to do it using scipy, is there another library/module i could use to do this ? Any suggestions/pointers/advice/hacks ? Thanks a ton, ashish -- “The best minds of my generation are thinking about how to make people click ads. That sucks.” - Jeff Hammerbacher (early fb engineer)

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NumPy 1.14.2 released
by Charles R Harris March 12, 2018

March 12, 2018

Hi All, I am pleased to announce the release of NumPy 1.14.2. This is a bugfix release for some bugs reported following the 1.14.1 release. The major problems dealt with are as follows. - Residual bugs in the new array printing functionality. - Regression resulting in a relocation problem with shared library. - Improved PyPy compatibility. This release supports Python 2.7 and 3.4 - 3.6. Wheels for the release are available on PyPI. Source tarballs, zipfiles, release notes, and the changelog are available on github <https://github.com/numpy/numpy/releases/tag/v1.14.2>. The Python 3.6 wheels available from PIP are built with Python 3.6.2 and should be compatible with all previous versions of Python 3.6. The source releases were cythonized with Cython 0.26.1, which is known to *not* support the upcoming Python 3.7 release. People who wish to run Python 3.7 should check out the NumPy repo and try building with the, as yet, unreleased master branch of Cython. Contributors ============ A total of 4 people contributed to this release. People with a "+" by their names contributed a patch for the first time. * Allan Haldane * Charles Harris * Eric Wieser * Pauli Virtanen Pull requests merged ==================== A total of 5 pull requests were merged for this release. * `#10674 <https://github.com/numpy/numpy/pull/10674>`__: BUG: Further back-compat fix for subclassed array repr * `#10725 <https://github.com/numpy/numpy/pull/10725>`__: BUG: dragon4 fractional output mode adds too many trailing zeros * `#10726 <https://github.com/numpy/numpy/pull/10726>`__: BUG: Fix f2py generated code to work on PyPy * `#10727 <https://github.com/numpy/numpy/pull/10727>`__: BUG: Fix missing NPY_VISIBILITY_HIDDEN on npy_longdouble_to_PyLong * `#10729 <https://github.com/numpy/numpy/pull/10729>`__: DOC: Create 1.14.2 notes and changelog. Cheers, Charles Harris

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Tessellating PointCloud (ConvexHull? Delaunay)
by Samuel Maybury March 7, 2018

March 7, 2018

Hi guys, Been looking to tesselate a 3D point cloud from array of form [[x1 y1 z1][x2 y2 z2]...[xn yn zn]]. I tried scipy.spatial.convexhull which worked decently, but has the notable limitation of not handling concaves. The STL I then extracted only had half the triangles, but I think I need to take that up with the maker of numpy-stl. Still kinda new to scipy (and programming in general) so could someone informed please help? From what I understand Delaunay triangulates every point in the cloud. Is there a way to limit it to only Tessellating to the nearest? Or a better method for doing this? Many thanks, Sam 3D Prints: 3dhubs.com/service/Mirths-Hub Connect: linkedin.com/samueljmaybury Watch: youtube.com/user/AcrimoniousMirth CV: engineering.community/profile/samuel-maybury/about

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what is signal.wiener?
by Neal Becker March 7, 2018

March 7, 2018

The wiener filter theory I'm familiar with requires specification of the autocorrelation matrix of the observed response and the cross-correlation between the target and the observation. What is it that signal.wiener actually does?

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ANN: SfePy 2018.1
by Robert Cimrman March 6, 2018

March 6, 2018

I am pleased to announce release 2018.1 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 (limited support). It is distributed under the new BSD license. Home page: http://sfepy.org Mailing list: https://mail.python.org/mm3/mailman3/lists/sfepy.python.org/ Git (source) repository, issue tracker: https://github.com/sfepy/sfepy Highlights of this release -------------------------- - major update of time-stepping solvers and solver handling - Newmark and Bathe elastodynamics solvers - interface to MUMPS linear solver - new examples: - iron plate impact problem (elastodynamics) - incompressible Mooney-Rivlin material model (hyperelasticity) as a script For full release notes see http://docs.sfepy.org/doc/release_notes.html#id1 (rather long and technical). Cheers, Robert Cimrman --- Contributors to this release in alphabetical order: Robert Cimrman Jan Heczko Jan Kopacka Vladimir Lukes

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Re: [SciPy-User] STL from nArray (Delauney)
by Hazen Babcock March 3, 2018

March 3, 2018

On 03/02/2018 11:17 PM, scipy-user-request(a)python.org wrote: > > Message: 3 > Date: Fri, 02 Mar 2018 22:44:04 +0000 > From: Samuel Maybury <samuel_maybury(a)me.com> > To: SciPy Users List <scipy-user(a)python.org> > Subject: Re: [SciPy-User] STL from nArray (Delauney) > Message-ID: <B30DC017-3135-4823-BD5D-A9A6DBD3A664(a)me.com> > Content-Type: text/plain; charset="utf-8" > > Hi Robert, > Thanks for your reply! I?ll take a look. The shapes that would be scanned are very simple: cylindrical with rounded end and no holes. Wouldn?t the triangulation be able to handle the tessellation of that? > > Many thanks, > Sam > If they are really simple you might consider programmatically creating an OpenSCAD file with the appropriate shapes (cylinder + sphere on the end?), then using OpenSCAD to create the STL file. http://www.openscad.org/ -Hazen

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Proposals, Query
by Hritik Narayan March 3, 2018

March 3, 2018

Are proposals to be posted on this mailing list, or should they be directly mailed to a mentor? --

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STL from nArray (Delauney)
by Samuel Maybury March 3, 2018

March 3, 2018

Hi all, I’m self-taught in Python for my university honours project and its been one hell of a journey. Simply put I’m designing a 3D scanner-printer hybrid to aid in the creation of prosthetic limbs. So long story short I’m running the system on an RPi and you can find more information here, if you want to help: https://github.com/AcrimoniousMirth/Project-Adam-3D-SCANNER-CODE <https://github.com/AcrimoniousMirth/Project-Adam-3D-SCANNER-CODE> So, in essence I have an array of form [[x1 y1 z1] [x2 y2 z2]… [xn yn zn]] and I need to turn it into an STL mesh. A forum member pointed me in the direction of scipy’s Delauney triangulation. Now, the values were appended into the array such that each group (of unknown size) will have the same z value and the next will have the closest z value to that. Due to how it was generated (with OpenCv) I can’t be entirely sure but I believe each group with the same z value was written in the same order and so the first of z1 should be close to the first of z2. Your help is greatly appreciated as this is very new territory to me and I’m not sure where to start. This is the final hurdle in the way of me graduating with a pretty good accreditation and two charities are interested in the idea so it’d be a blessing to get it working! Many thanks, Sam

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