Mailman 3 August 2006 - SciPy-User

Help required regding Eigenvectors
by Sudheer Phani March 14, 2022

March 14, 2022

Hello All, I have been encountering some strange problems with the calculation of eigen vectors using python. The problem is with the sign of the eigen vectors calculated. On Very few occasions the eigen vectors calculated using python have an opposite sign than the actual eigenvectors, though the magnitude is correct. Can any one of you plz help me in this regard and suggest me some solution if you have encoutered similar problems . Any help in this regd is appreciated Thanks in Advace regds Sudheer

5 5

3D plotting
by Robert Cimrman Sept. 10, 2009

Sept. 10, 2009

Hi, I need to do some simple 3D plots, so I tried the two Cookbook recipes (xplt, mplot3d) and failed: * xplt: does not work when using a custom installation directory such as python setup.py install --root=/home/share/software apparently the gistdata directory path is wrong: gist.error: failed to create drawing -- Gist work.gs style sheet missing * mplot3d: does not work with my version of matplotlib (0.80). I have made the changes mentioned in the Cookbook to no avail. (Axes.__init__() args apparently changed, as well as some other matplotlib object attributes) Any ideas? mplot3d looks great, I would really like to use it! thanks, r.

6 6

FAIL: check_dot (scipy.linalg.tests.test_blas.test_fblas1_simple)
by Andrew Jaffe Nov. 16, 2006

Nov. 16, 2006

Hi All- I get the following error with scipy.__version__ = '0.5.0.2121' on PPC OSX 2.4.3 Universal Build with numpy 1.0.2889 (note that the latter has a known longdouble problem, but I don't think that's related). Indeed the fblas complex [c,z]dot[c,u] functions do seem to fail. (In fact, zdotc([1,-4,3],[2,3,1]) hangs the interpreter...) Andrew ====================================================================== FAIL: check_dot (scipy.linalg.tests.test_blas.test_fblas1_simple) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/scipy-0.5.0.2121-py2.4-macosx-10.3-fat.egg/scipy/linalg/tests/test_blas.py", line 75, in check_dot assert_almost_equal(f([3j,-4,3-4j],[2,3,1]),-9+2j) File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/numpy-1.0.2889-py2.4-macosx-10.3-fat.egg/numpy/testing/utils.py", line 156, in assert_almost_equal assert round(abs(desired - actual),decimal) == 0, msg AssertionError: Items are not equal: ACTUAL: (-1.9980511665344238+2.1130658899732593e-36j) DESIRED: (-9+2j) ====================================================================== FAIL: check_dot (scipy.lib.tests.test_blas.test_fblas1_simple) ---------------------------------------------------------------------- Traceback (most recent call last): File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/scipy-0.5.0.2121-py2.4-macosx-10.3-fat.egg/scipy/lib/blas/tests/test_blas.py", line 76, in check_dot assert_almost_equal(f([3j,-4,3-4j],[2,3,1]),-9+2j) File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/numpy-1.0.2889-py2.4-macosx-10.3-fat.egg/numpy/testing/utils.py", line 156, in assert_almost_equal assert round(abs(desired - actual),decimal) == 0, msg AssertionError: Items are not equal: ACTUAL: (-1.9980511665344238+2.1996782422872647e-36j) DESIRED: (-9+2j)

1 1

global fitting of data sets with common parameters
by morovia morovia Sept. 26, 2006

Sept. 26, 2006

Hello I have data sets and would like to fit them globally with common parameters. Is there a way to do this using existing scipy modules leastsq. Any pointers for algo and suggestions are welcome. Thanks Morovia.

3 7

on global fitting for sets of data
by morovia morovia Sept. 22, 2006

Sept. 22, 2006

Hello I have data sets and would like to fit them globally with common parameters. Is there a way to do this using existing scipy modules leastsq. Any pointers for algo and suggestions are welcome. Thanks Morovia.

3 2

Triangulation of L-shaped domains
by Nils Wagner Sept. 6, 2006

Sept. 6, 2006

Hi all, I have installed delaunay from the sandbox. How can I triangulate L-shaped domains ? My first try is somewhat unsatisfactory (delaunay.png) ? How can I remove the unwanted triangles down to the right ? Nils

7 19

amd64 specific error in fitpack spline interpolation
by Angus McMorland Sept. 5, 2006

Sept. 5, 2006

Hi all, I posted about this problem a few months ago, but we didn't get very far, but the annoyance level of the problem is enough now for me to have another go. I'm trying to run the spline example from the cookbook (my exact code, called spl.py, is inlined below). On an ix86 computer this works fine, and returns the expected graphs, but on an amd64 machine I get the error below. Both computers are running debian etch, with recent svn numpy and scipy. TypeError: array cannot be safely cast to required type > /usr/lib/python2.4/site-packages/scipy/interpolate/fitpack.py(217)splprep() 216 t,c,o=_fitpack._parcur(ravel(transpose(x)),w,u,ub,ue,k,task,ipar,s,t, --> 217 nest,wrk,iwrk,per) 218 _parcur_cache['u']=o['u'] I believe the error is generated by the _parcur call -> once in pdb, calling it again re-raises the same error. ipdb>_fitpack._parcur(ravel(transpose(x)),w,u,ub,ue,k,task,ipar,s,t, nest,wrk,iwrk,per) *** TypeError: array cannot be safely cast to required type I've checked the values of all the inputs to the call ravel(transpose(x)) | shape=(300,) <type 'numpy.float64'> w | shape=(100,) <type 'numpy.float64'> u | shape=(100,) <type 'numpy.float64'> ub | 0 <type 'int'> ue | 1 <type 'int'> k | 2 <type 'int'> task | 0 <type 'int'> ipar | F <type 'bool'> s | 3.0 <type 'float'> t | [] <type 'numpy.ndarray'> nest | 103 <type 'int'> wrk | [] <type 'numpy.ndarray'> iwrk | [] <type 'numpy.ndarray'> per | 0 <type 'int'> and they are all the same on both machines, suggesting to me that something is happening wrong in the internals of the function call, rather than with one of the parameters. Any suggestions what could be going on, or how I could debug this further? Can anyone at least verify that the problem exists on other amd64 platforms. Thanks, Angus. spl.py: -------------------------------- from numpy import arange, cos, linspace, pi, sin from scipy.interpolate import splprep, splev from numpy.random import randn # make ascending spiral in 3-space t=linspace(0,1.75*2*pi,100) x = sin(t) y = cos(t) z = t # add noise x+= 0.1*randn(*x.shape) y+= 0.1*randn(*y.shape) z+= 0.1*randn(*z.shape) # spline parameters s=3.0 # smoothness parameter k=2 # spline order nest=-1 # estimate of number of knots needed (-1 = maximal) # find the knot points tckp,u = splprep([x,y,z],s=s,k=k,nest=-1) # evaluate spline, including interpolated points xnew,ynew,znew = splev(linspace(0,1,400),tckp) import pylab pylab.subplot(2,2,1) data,=pylab.plot(x,y,'bo-',label='data') fit,=pylab.plot(xnew,ynew,'r-',label='fit') pylab.legend() pylab.xlabel('x') pylab.ylabel('y') pylab.subplot(2,2,2) data,=pylab.plot(x,z,'bo-',label='data') fit,=pylab.plot(xnew,znew,'r-',label='fit') pylab.legend() pylab.xlabel('x') pylab.ylabel('z') pylab.subplot(2,2,3) data,=pylab.plot(y,z,'bo-',label='data') fit,=pylab.plot(ynew,znew,'r-',label='fit') pylab.legend() pylab.xlabel('y') pylab.ylabel('z') -- Angus McMorland email a.mcmorland(a)auckland.ac.nz mobile +64-21-155-4906 PhD Student, Neurophysiology / Multiphoton & Confocal Imaging Physiology, University of Auckland phone +64-9-3737-599 x89707 Armourer, Auckland University Fencing Secretary, Fencing North Inc.

6 6

Problem with Windows Scipy 0.5
by Tony Triolo Aug. 31, 2006

Aug. 31, 2006

I've been trying to use Scipy 0.5 with Python 2.4 for Windows and can't seem to get it to play nicely with any version of Numpy. Here is what I have tried along with the result: ********************************* Python 2.4.3 (#69, Mar 29 2006, 17:35:34) [MSC v.1310 32 bit (Intel)] on win32 Type "copyright", "credits" or "license()" for more information. **************************************************************** Personal firewall software may warn about the connection IDLE makes to its subprocess using this computer's internal loopback interface. This connection is not visible on any external interface and no data is sent to or received from the Internet. **************************************************************** IDLE 1.1.3 >>> import numpy,scipy Overwriting info=<function info at 0x00EB83F0> from scipy.misc.helpmod (was <function info at 0x00E6BEF0> from numpy.lib.utils) Overwriting who=<function who at 0x00EAF730> from scipy.misc.common (was <function who at 0x00E6BE30> from numpy.lib.utils) Overwriting source=<function source at 0x00EBD570> from scipy.misc.helpmod (was <function source at 0x00E6BF30> from numpy.lib.utils) RuntimeError: module compiled against version 1000000 of C-API but this version of numpy is 1000002 ********************************** The installer used for Scipy was : scipy-0.5.0.win32-py2.4.exe and the installer for Numpy was : numpy-1.0b4.win32-py2.4.exe I've tried Numpy 0.9.8 and 0.9.6 with the same result. I've also tried on Windows XP and 2000 machines. Before I go trying to make my own Numpy and Scipy builds, any ideas on how I can successfully install SciPy on a Windows machine with the available binaries? I don't have an out of the ordinary PC configuration and figured the binaries on the download site should work just fine. Has anyone tested the SciPy install on Win2000 or WinXP Pentium 4 machines? Thanks. -Tony ----------------------------------------------- Anthony A. Triolo, Ph.D. Senior Scientist Telcordia Technologies (732) 758 - 3098 -----------------------------------------------

2 1

Academic Question?
by Conor Robinson Aug. 31, 2006

Aug. 31, 2006

Hello scipy users, If one is using 1ofC encoding, what does PCA applied to 1ofC result in? 1ofc is nice if you're trying to get the posterior probability distribution as output (sigmoid single output unit feedforward network), however would this still hold true after applying PCA to reduce input dimensionality? Does this even make "sense" for 1ofc? Furthermore, is there any solid literature reviewing encoding schemes for nnets etc? Thanks, Conor

3 4

global fitting of data sets with linked paramters
by morovia morovia Aug. 31, 2006

Aug. 31, 2006

Hello I have data sets and would like to fit them globally with common parameters. Is there a way to do this using existing scipy modules leastsq. Any pointers for algo and suggestions are welcome. Thanks Morovia.

1 0