Mailman 3 December 2008 - 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

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scipy/numpy on CentOS 5/ Dependency problem
by Matthias Blaicher Dec. 8, 2010

Dec. 8, 2010

Hello, I want to install SciPy and numpy on a CentOS 5 system. It contains a fresh install with up-to-date packages. I use the "official" Suse Build repos by DavidCournapeau. It fails with a conflict between refblas3 and blas. [root@localhost yum.repos.d]# yum install python-numpy python-scipy Loading "fastestmirror" plugin Loading mirror speeds from cached hostfile * home_ashigabou: download.opensuse.org * extras: mirrors.tummy.com * updates: dds.gina.alaska.edu * base: mirror.hmc.edu * addons: mirrors.tummy.com extras 100% |=========================| 1.1 kB 00:00 updates 100% |=========================| 951 B 00:00 base 100% |=========================| 1.1 kB 00:00 addons 100% |=========================| 951 B 00:00 Setting up Install Process Parsing package install arguments Resolving Dependencies --> Running transaction check ---> Package python-scipy.i386 0:0.6.0-2.1 set to be updated --> Processing Dependency: libblas.so.3 for package: python-scipy --> Processing Dependency: libblas.so.3 for package: python-scipy --> Processing Dependency: liblapack.so.3 for package: python-scipy --> Processing Dependency: libgfortran.so.1 for package: python-scipy --> Processing Dependency: liblapack.so.3 for package: python-scipy ---> Package python-numpy.i386 0:1.2.0-1.1 set to be updated --> Processing Dependency: gcc-gfortran for package: python-numpy --> Processing Dependency: refblas3 for package: python-numpy --> Processing Dependency: lapack3 < 3.1 for package: python-numpy --> Running transaction check ---> Package gcc-gfortran.i386 0:4.1.2-42.el5 set to be updated --> Processing Dependency: gcc = 4.1.2-42.el5 for package: gcc-gfortran ---> Package blas.i386 0:3.0-37.el5 set to be updated ---> Package lapack3.i386 0:3.0-19.1 set to be updated ---> Package lapack.i386 0:3.0-37.el5 set to be updated ---> Package refblas3.i386 0:3.0-11.1 set to be updated ---> Package libgfortran.i386 0:4.1.2-42.el5 set to be updated --> Running transaction check ---> Package gcc.i386 0:4.1.2-42.el5 set to be updated --> Processing Dependency: libgomp.so.1 for package: gcc --> Processing Dependency: glibc-devel >= 2.2.90-12 for package: gcc --> Processing Dependency: libgomp = 4.1.2-42.el5 for package: gcc --> Running transaction check ---> Package glibc-devel.i386 0:2.5-24 set to be updated --> Processing Dependency: glibc-headers for package: glibc-devel --> Processing Dependency: glibc-headers = 2.5-24 for package: glibc-devel ---> Package libgomp.i386 0:4.1.2-42.el5 set to be updated --> Running transaction check ---> Package glibc-headers.i386 0:2.5-24 set to be updated --> Processing Dependency: kernel-headers for package: glibc-headers --> Processing Dependency: kernel-headers >= 2.2.1 for package: glibc-headers --> Running transaction check ---> Package kernel-headers.i386 0:2.6.18-92.1.13.el5 set to be updated --> Processing Conflict: refblas3 conflicts blas --> Finished Dependency Resolution Error: refblas3 conflicts with blas Is there anything I'm doing wrong here, as I don't want to compile all dependencies by myself.. Sincerly, Matthias Blaicher

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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.

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assign to diagonal values?
by Carlos Scheidegger July 7, 2009

July 7, 2009

Say I have a matrix m whose diagonal values I want to replace with the contents of vector new_diagonal. Right now, I'm using m -= diag(m) m += diag(new_diagonal) but that seems pretty wasteful (especially if diag() creates new arrays, which I suspect it does). Is there a standard (or any efficient) way to assign the diagonal values directly without an explicit for loop? Googling for "site:www.scipy.org assign diagonal" only returned results for sparse matrices, which is not the case here - these are plain numpy arrays. Thanks in advance, -carlos

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Is numpy's argsort lying about its numpy.int32 types?
by Rob Clewley May 15, 2009

May 15, 2009

Hi, I'm having a problem comparing some types when using numpy's argsort. I'm using numpy 1.0.2. I can reproduce it simply: Python 2.4.4 (#71, Oct 18 2006, 08:34:43) [MSC v.1310 32 bit (Intel)] << snip >> In [1]: from numpy import argsort, sort, int32, array In [2]: x=array([1,3,2]) In [3]: aa=argsort(x) In [4]: as=sort(x) In [5]: type(aa[0]) Out[5]: <type 'numpy.int32'> In [6]: type(as[0]) Out[6]: <type 'numpy.int32'> In [7]: int32 Out[7]: <type 'numpy.int32'> In [8]: type(as[0])==int32 Out[8]: True In [9]: type(aa[0])==int32 Out[9]: False Any of the three indices in aa give me the same problem. Can someone explain if I should be doing this a different way, and if this is a bug?! Thanks, Rob

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signal.lti(A,B,C,D) with D=0
by William Purcell Feb. 18, 2009

Feb. 18, 2009

I am trying to set up state space representation of a system using signal.lti. The system has no feedforward so D = 0. I've tried the three options listed in the code below to represent D. The only way I can get it to work is option 2 if C has 1 row. If C has more than 1 row it won't work. Any thoughts? -Bill Code --------------------------------------------------------------- from numpy import ones,matrix from scipy import signal r = ones(3) A = matrix([r,r,r]) B = matrix([r]).T C = matrix([r,r]) #three options of D to make it 0 #1) D=0 #2) D = matrix([0,0]).T #3) D = None D = 0 #D = None #D = matrix([0,0]).T Gss = signal.lti(A,B,C,D) ----------------------------------------------------------- Tracebacks ----------------------------------------------------------- Option 1 /usr/lib/python2.5/site-packages/scipy/signal/ltisys.py in abcd_normalize(A, B, C, D) 101 raise ValueError, "A and C must have the same number of columns." 102 if MD != MC: --> 103 raise ValueError, "C and D must have the same number of rows." 104 if ND != NB: 105 raise ValueError, "B and D must have the same number of columns." <type 'exceptions.ValueError'>: C and D must have the same number of rows. WARNING: Failure executing file: <testlti.py> Option 2 (with C as two rows...if C is a single row I do not get this traceback) /usr/lib/python2.5/site-packages/scipy/signal/ltisys.py in ss2tf(A, B, C, D, input) 147 148 num_states = A.shape[0] --> 149 type_test = A[:,0] + B[:,0] + C[0,:] + D 150 num = numpy.zeros((nout, num_states+1), type_test.dtype) 151 for k in range(nout): <type 'exceptions.ValueError'>: shape mismatch: objects cannot be broadcast to a single shape WARNING: Failure executing file: <testlti.py> Option 3 same as 1

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looking for a consultant for the design of an interface for our mathematical models
by Marko Loparic Jan. 6, 2009

Jan. 6, 2009

Hi, I am looking for someone that could help us to design (perhaps also to implement) a user interface (GUI + repository of data) for our mathematical models. I work for a company in the energy sector. Currently in our department we have 5 different mathematical models using different GUIs and excel hacks to allow users to feed the data and get results. We would like to have a single, powerful, user-friendly interface for all those models. We need the help of an experienced and inventive software designer to help us to choose the technology to use and to make the design (possibly also the implementation) of the tool. Of course we would like to reuse existing tools whenever possible. We propose to pay for one or two days of consultancy when we will describe our needs and discuss the possible design choices. Depending on the conclusions we get we can work further together. We are located near Brussels. Usage of python is not a request but it is a natural choice since it is the main language we use. Any indication on how I can find the good person for the job would be of great help! Thank you very much! Marko

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[ Python(x,y) ] New release : 2.1.7
by Pierre Raybaut Dec. 29, 2008

Dec. 29, 2008

Hi all, Release 2.1.7 is now available on http://www.pythonxy.com: - All-in-One Installer ("Full Edition"), - Plugin Installer -- to be downloaded with xyweb, - Update New important feature (see below, the main installer 'package manager mode' - introduced with Python(x,y) 2.1.6): now you may update your Python(x,y) installation directly with the main installer (or as before using the update installer, or by installing directly the plugins to update as before too). Changes history Version 2.1.7 (12-29-2008) * Added: o PyVISA 1.3 - Control all kinds of measurement equipment through various busses (GPIB, RS232, USB) o Python(x,y) installer - 'packet manager mode': now allows the user to update installed plugins (and, as before, to install/uninstall plugins) - compatible with all 2.1.x releases of Python(x,y) * Updated: o Console 2.0.141.5 o Winpdb 1.4.2.1 o pylint 0.15.2.1 - pylint is now disabled by default * Corrected: o Python(x,y) Plugin Installer: MinGW and SWIG directory customization pages were not shown Regards, Pierre Raybaut

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Is it possible with scipy?
by olfa mraihi Dec. 24, 2008

Dec. 24, 2008

Hello Scipy community, I want to know if Scipy could deal with symbolic arrays and lists (by symbolic I mean without specifying the concrete contents of list or array) For example I want to solve a system of equations containing lists and arrays like this solve(x+Sum[A[k],k=i..N]==y+Sum[B[k],k=m..N], j-Length[C]==l-Length[D], z/(c ^ i)==t/(c ^ h), u+1==2*v-3w, v=f(f(w))) (here A and B are arrays; C et D are lists; x,y,z,t,j,l,i,h,u,v,w are variables that could be of type integer or real, c is a constant and f is a function): Thank you very much. Yours faithfully, Olfa MRAIHI

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[ Python(x,y) ] New release : 2.1.6
by Pierre Raybaut Dec. 23, 2008

Dec. 23, 2008

Hi all, Release 2.1.6 is now available on http://www.pythonxy.com: - All-in-One Installer ("Full Edition"), - Plugin Installer -- to be downloaded with xyweb, - Update (soon available) Important new feature: After installing Python(x,y), you may run the installer again (All-in-One or Plugin Installer) to add/remove plugins. Changes history Version 2.1.6 (12-23-2008) * Added: o pylint 0.15.2 - Logilab code analysis module: analyzes Python source code looking for bugs and signs of poor quality o NetworkX 0.99 - Creation, manipulation, and study of the structure, dynamics, and functions of complex networks o PyQwt3D 0.1.6 - 3D plotting library (set of Python bindings for the Qwt3D library) o PyOpenGL 3.0.0.8 - Cross platform Python binding to OpenGL and related APIs o cvxopt 1.1 - Convex optimization library o winpdb 1.4.2 - Enhanced Python debugger, 20 times faster than pdb o PyGTK 2.12.1 - GUI toolkit based on GTK+ o h5py 1.0.1 - General-purpose Python interface to HDF5 files (unlike PyTables, h5py provides direct access to the full HDF5 C library) o pydicom 0.9.1 - Pure python package for working with DICOM files o Start Menu shortcut: compile (optimize) installed modules (*.py -> *.pyo) * Updated: o NumPy 1.2.1.1 (added: a lot of documentation) o SciPy 0.6.0.3 (added: a lot of documentation) o matplotlib 0.98.5.2 o Enthought Tool Suite 3.1.0 o Cython 0.10.3 o IPython 0.9.1.5 o SymPy 0.6.3 o PySQlite 2.5.1 o PyTables 2.1 o Sphinx 0.5.1 o xy 1.0.15 o MinGW 3.4.5.5 o Pydev 1.4.1 o StartExplorer 0.4.0 (Eclipse plugin) o Notepad++ 5.1.2 o Console 2.0.141.4 o Following updates are relevant only for a new install of Python(x,y) (there is absolutely no need to update your current install) o Eclipse 3.4.1.2 * Corrected: o Issues 39, 44, 45 Regards, Pierre Raybaut

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