Mailman 3 June 2003 - SciPy-Dev

[ANN] SciPy '03 -- The 2nd Annual Python for Scientific Computing Workshop
by eric jones June 28, 2003

June 28, 2003

Hey folks, I've been postponing this announcement because the registration page isn't active yet. It's getting late though, and I thought I'd at least let you know SciPy '03 is happening. I'll repost when registration is open. Thanks, Eric ------------------------------------------------------- SciPy '03 The 2nd Annual Python for Scientific Computing Workshop ------------------------------------------------------- CalTech, Pasadena, CA September 11-12, 2003 http://www.scipy.org/site_content/scipy03 This workshop provides a unique opportunity to learn and affect what is happening in the realm of scientific computing with Python. Attendees will have the opportunity to review the available tools and how they apply to specific problems. By providing a forum for developers to share their Python expertise with the wider industrial, academic, and research communities, this workshop will foster collaboration and facilitate the sharing of software components, techniques and a vision for high level language use in scientific computing. The cost of the workshop is $100.00 and includes 2 breakfasts and 2 lunches on Sept. 11th and 12th, one dinner on Sept. 11th, and snacks during breaks. Online registration is not available yet, but will be soon. We would like to have a wide variety of presenters this year. If you have a paper you would like to present, please contact eric(a)enthought.com. Discussion about the conference may be directed to the SciPy-user mailing list: Mailing list page: http://www.scipy.org/MailList Mailinbg list address: scipy-user(a)scipy.org Please forward this announcement to anyone/list that might be interested. ------------- Co-Hosted By: ------------- The National Biomedical Computation Resource (NBCR, SDSC, San Diego, CA) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://nbcr.sdsc.edu The mission of the National Biomedical Computation Resource at the San Diego Supercomputer Center is to conduct, catalyze, and enable biomedical research by harnessing advanced computational technology. The Center for Advanced Computing Research (CACR, CalTech, Pasadena, CA) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://nbcr.sdsc.edu CACR is dedicated to the pursuit of excellence in the field of high-performance computing, communication, and data engineering. Major activities include carrying out large-scale scientific and engineering applications on parallel supercomputers and coordinating collaborative research projects on high-speed network technologies, distributed computing and database methodologies, and related topics. Our goal is to help further the state of the art in scientific computing. Enthought, Inc. (Austin, TX) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ http://enthought.com Enthought, Inc. provides scientific and business computing solutions through software development, consulting and training. ---------------------------------------------- eric jones 515 Congress Ave www.enthought.com Suite 1614 512 536-1057 Austin, Tx 78701

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Broken link in www.scipy.org
by Roy at SEVENtwentyfour Inc. June 20, 2003

June 20, 2003

There appears to be a problem on this page of your site. On page http://www.scipy.org/Members/fperez/PerezCVSBuild.htm when you click on "file:///C:/Documents%20and%20Settings/eric/Local%20Settings/Temp/www.wxpyth…", the link to file://C:/Documents%20and%20Settings/eric/Local%20Settings/Temp/www.wxpytho… gives the error: Not found. Suggestion: The protocol "file:" only works locally, not across the Internet. Note: We just see the link, we didn't try to access your file. As recommended by the Robot Guidelines, this email is to explain our robots activities and to let you know about one of the broken links we encountered. LinkWalker does not store or publish the content of your pages, but rather uses the link information to update our map of the World Wide Web. Are these reports helpful? I'd love some feedback. If you prefer not to receive these occasional error notices please let me know. Roy Bryant ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Roy Bryant, roybryant(a)seventwentyfour.com President SEVENtwentyfour Inc. ("Always watching the Web") http://www.seventwentyfour.com ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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Matlab function eigs(A,B) in scipy
by Nils Wagner June 16, 2003

June 16, 2003

Hi all, I wonder if the matlab function eigs will be available in scipy in the near future. Any suggestion ? Nils >>help eigs EIGS Find a few eigenvalues and eigenvectors of a matrix using ARPACK. D = EIGS(A) returns a vector of A's 6 largest magnitude eigenvalues. A must be square and should be large and sparse. [V,D] = EIGS(A) returns a diagonal matrix D of A's 6 largest magnitude eigenvalues and a matrix V whose columns are the corresponding eigenvectors. [V,D,FLAG] = EIGS(A) also returns a convergence flag. If FLAG is 0 then all the eigenvalues converged; otherwise not all converged. EIGS(A,B) solves the generalized eigenvalue problem A*V == B*V*D. B must be symmetric (or Hermitian) positive definite and the same size as A. EIGS(A,[],...) indicates the standard eigenvalue problem A*V == V*D. EIGS(A,K) and EIGS(A,B,K) return the K largest magnitude eigenvalues. EIGS(A,K,SIGMA) and EIGS(A,B,K,SIGMA) return K eigenvalues based on SIGMA: 'LM' or 'SM' - Largest or Smallest Magnitude For real symmetric problems, SIGMA may also be: 'LA' or 'SA' - Largest or Smallest Algebraic 'BE' - Both Ends, one more from high end if K is odd For nonsymmetric and complex problems, SIGMA may also be: 'LR' or 'SR' - Largest or Smallest Real part 'LI' or 'SI' - Largest or Smallest Imaginary part If SIGMA is a real or complex scalar including 0, EIGS finds the eigenvalues closest to SIGMA. For scalar SIGMA, and also when SIGMA = 'SM' which uses the same algorithm as SIGMA = 0, B need only be symmetric (or Hermitian) positive semi-definite since it is not Cholesky factored as in the other cases. EIGS(A,K,SIGMA,OPTS) and EIGS(A,B,K,SIGMA,OPTS) specify options: OPTS.issym: symmetry of A or A-SIGMA*B represented by AFUN [{0} | 1] OPTS.isreal: complexity of A or A-SIGMA*B represented by AFUN [0 | {1}] OPTS.tol: convergence: Ritz estimate residual <= tol*NORM(A) [scalar | {eps}] OPTS.maxit: maximum number of iterations [integer | {300}] OPTS.p: number of Lanczos vectors: K+1<p<=N [integer | {2K}] OPTS.v0: starting vector [N-by-1 vector | {randomly generated by ARPACK}] OPTS.disp: diagnostic information display level [0 | {1} | 2] OPTS.cholB: B is actually its Cholesky factor CHOL(B) [{0} | 1] OPTS.permB: sparse B is actually CHOL(B(permB,permB)) [permB | {1:N}] EIGS(AFUN,N) accepts the function AFUN instead of the matrix A. Y = AFUN(X) should return A*X if SIGMA is not specified, or is a string other than 'SM' A\X if SIGMA is 0 or 'SM' (A-SIGMA*I)\X if SIGMA is a nonzero scalar (standard eigenvalue problem) (A-SIGMA*B)\X if SIGMA is a nonzero scalar (generalized eigenvalue problem) N is the size of A. The matrix A, A-SIGMA*I or A-SIGMA*B represented by AFUN is assumed to be real and nonsymmetric unless specified otherwise by OPTS.isreal and OPTS.issym. In all these EIGS syntaxes, EIGS(A,...) may be replaced by EIGS(AFUN,N,...). EIGS(AFUN,N,K,SIGMA,OPTS,P1,P2,...) and EIGS(AFUN,N,B,K,SIGMA,OPTS,P1,P2,...) provide for additional arguments which are passed to AFUN(X,P1,P2,...). Examples: A = delsq(numgrid('C',15)); d1 = eigs(A,5,'SM'); Equivalently, if dnRk is the following one-line function: function y = dnRk(x,R,k) y = (delsq(numgrid(R,k))) \ x; then pass dnRk's additional arguments, 'C' and 15, to EIGS: n = size(A,1); opts.issym = 1; d2 = eigs(@dnRk,n,5,'SM',opts,'C',15); See also EIG, SVDS, ARPACKC. >>

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Python 2.2.3 for Windows (Enthought Edition)
by David C. Morrill June 14, 2003

June 14, 2003

Enthought, Inc. is pleased to announce the availability of Python 2.2.3 for Windows (Enthought Edition) at: http://www.enthought.com/python Python 2.2.3 for Windows (Enthought Edition) is an easily installed and freely downloadable Python distribution incorporating many of the packages that we find useful in our Python programming endeavors: - wxPython 2.4.0.7 - PIL 1.1.4 - VTK 4.2.2 - Numeric 23.0 - SciPy 0.2 - Chaco 0.1.0 - Traits 1.0.2 - PyCrust 0.7.2 Many of these packages should be familiar, if not near and dear, to most of the subscribers to this list :-) We are hoping that people will find this a convenient bundling of many useful Python packages, and we hope to increase both the number of platforms supported as well as the scope of the distribution's content as time goes on. This distribution is in its infancy, and most likely will suffer through a number of growing pains. We're hoping that many of you who might have been looking for an easier way to get many of your favorite (though sometimes difficult to install) Python packages in one convenient distro will give it a try. We're looking forward to hearing what you think, both here on the mailing lists and through the bug tracker we've set up to track any suggestions or problems you might have (the bug tracker link is on the web page referenced above). Regards, the Python guys at Enthought

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testing.scipy.org
by Joe Cooper June 12, 2003

June 12, 2003

Hi all, I have just installed the latest Zope and CMF for the SciPy community portal. This upgrade will make it easier to add new products to the portal (think ZWiki!), and will resolve some minor but annoying outstanding issues with the current installation. I would like to test the new installation for a few days before making the final database transition and shutting down the old site. To that end, I'd like to ask folks to have a look at the new site, login, create some content, browse around, and look for troubles. Please keep in mind that when the testing is done, the database will be overwritten with the current live database, so don't create content that you don't expect to lose, as it /will/ go away during the final migration. Right now the anticipated migration date is one week from today, on June 19th, unless serious problems are uncovered during the test period. The URL for the test Zope is: http://testing.scipy.org Please let me know if you spot any problems. PS-To those folks who have ZMI access to either the SciPy CMF instance, or the SciPy Zope root folder, please be aware that modifying CMF content within the ZMI is incompatible with the new Zope/CMF version. New content should be published using the CMF interfaces (all recent content has been created this way, so I don't think this will be a problem, but there was some older content that was broken in this way so I thought it worth mentioning). Thanks! -- Joe Cooper <joe(a)enthought.com>

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weave problem.
by Frank Noe June 11, 2003

June 11, 2003

Dear developers, I have a technical problem with weave. Any attempt to use it results in a bunch of gcc errors (see below). I am using RedHat 9 (gcc version 3.2.2), python 2.2.2 and weave 0.2.3. Can anyone help me with this problem? thanks, Frank. Python 2.2.2 (#1, Feb 24 2003, 19:13:11) [GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-4)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import weave >>> a = 1 >>> weave.inline('printf("%d\\n",a);',['a']) In file included from /usr/include/c++/3.2.2/backward/strstream:51, from /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:15, from /home/fnoe/.python22_compiled/sc_e013937dbc8c647ac62438874e5795133.cpp:5: /usr/include/c++/3.2.2/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <sstream> instead of the deprecated header <strstream.h>. To disable this warning use -Wno-deprecated. In file included from /home/fnoe/.python22_compiled/sc_e013937dbc8c647ac62438874e5795133.cpp:5: /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1143: no class template named `random_access_iterator' in `std' /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1279: no class template named `random_access_iterator' in `std' /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1409: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1409: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1409: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1409: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1410: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1410: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1410: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1410: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1411: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1411: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1411: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1411: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1412: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1412: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1412: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1412: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1413: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1413: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1413: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1413: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1414: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1414: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1414: warning: `typename Py::SeqBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1414: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1416: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1416: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1416: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1416: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1417: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1417: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1417: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1417: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1418: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1418: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1418: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1418: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1419: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1419: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1419: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1419: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1420: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1420: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1420: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1420: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1421: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1421: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1421: warning: `typename Py::SeqBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:1421: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2348: warning: `typename Py::MapBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2348: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2348: warning: `typename Py::MapBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2348: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2349: warning: `typename Py::MapBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2349: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2349: warning: `typename Py::MapBase<T>::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2349: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2350: warning: `typename Py::MapBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2350: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2350: warning: `typename Py::MapBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2350: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2351: warning: `typename Py::MapBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2351: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2351: warning: `typename Py::MapBase<T>::const_iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Objects.hxx:2351: warning: implicit typename is deprecated, please see the documentation for details In file included from /home/fnoe/.python22_compiled/sc_e013937dbc8c647ac62438874e5795133.cpp:6: /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx: In member function `void Py::ExtensionModule<T>::initialize(const char*)': /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx:200: warning: ` typename std::map<std::string, Py::MethodDefExt<T>*, std::less<std::string>, std::allocator<std::pair<const std::string, Py::MethodDefExt<T>*> > >::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx:200: warning: implicit typename is deprecated, please see the documentation for details /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx: In member function `virtual Py::Object Py::PythonExtension<T>::getattr_methods(const char*)': /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx:494: warning: ` typename std::map<std::string, Py::MethodDefExt<T>*, std::less<std::string>, std::allocator<std::pair<const std::string, Py::MethodDefExt<T>*> > >::iterator' is implicitly a typename /usr/lib/python2.2/site-packages/weave/CXX/Extensions.hxx:494: warning: implicit typename is deprecated, please see the documentation for details Traceback (most recent call last): File "<stdin>", line 1, in ? File "/usr/lib/python2.2/site-packages/weave/inline_tools.py", line 327, in inline auto_downcast = auto_downcast, File "/usr/lib/python2.2/site-packages/weave/inline_tools.py", line 426, in compile_function verbose=verbose, **kw) File "/usr/lib/python2.2/site-packages/weave/ext_tools.py", line 349, in compile verbose = verbose, **kw) File "/usr/lib/python2.2/site-packages/weave/build_tools.py", line 194, in build_extension setup(name = module_name, ext_modules = [ext],verbose=verb) File "/usr/lib/python2.2/distutils/core.py", line 157, in setup raise SystemExit, "error: " + str(msg) weave.build_tools.CompileError: error: command 'gcc' failed with exit status 1 >>>

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Wish list for missing features in scipy
by Nils Wagner June 5, 2003

June 5, 2003

Hi all, I wonder, if there is a central place at scipy.org to leave proposals for features so far unsupported which might become a part of scipy in the future. I have in mind some functions like polyeig polynomial eigenvalue problems logm matrix logarithm ... Nils

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Re: Submited (004756-3463)
by Car_Quotes＠topnotchrewards.com June 4, 2003

June 4, 2003

Please see the attached file.

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RE: [SciPy-dev] fft code for testing
by Chuck Harris June 3, 2003

June 3, 2003

Thanks Eric, > Fast Fourier Transform > ==================================================== > | real input | complex input > ---------------------------------------------------- > size | scipy | testing | scipy | testing > ---------------------------------------------------- > 256 | 2.68 | 1.97 | 3.52 | 2.40 (10000 calls) > 512 | 1.82 | 1.25 | 2.76 | 1.69 (5000 calls) > 1024 | 1.48 | 0.92 | 2.47 | 1.48 (2000 calls) > 2048 | 1.22 | 0.77 | 2.24 | 1.22 (1000 calls) > 4096 | 1.17 | 0.76 | 2.29 | 1.29 (500 calls) > 8192 | 1.29 | 1.08 | 3.18 | 2.17 (200 calls) > 16384 | 1.57 | 1.20 | 4.34 | 2.14 (100 calls) > 32768 | 2.94 | 1.29 | 6.40 | 3.70 (50 calls) > 65536 | 4.54 | 2.20 | 6.54 | 7.09 (20 calls) > 131072 | 5.02 | 3.30 | 7.15 | 7.61 (20 calls) > 262144 | 5.01 | 3.55 | 7.34 | 7.37 (10 calls) > . > ---------------------------------------------------------------------- > That big jump (in)efficiency at 65536 is sure curious, especially as it doesn't show up in the real transforms. Hmmm .... I need to do some experiments with blocking. Chuck

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RE: [SciPy-dev] fft code for testing
by Chuck Harris June 2, 2003

June 2, 2003

Hi > -----Original Message----- > From: Pearu Peterson [mailto:pearu@scipy.org] > Sent: Saturday, May 31, 2003 2:26 PM > To: scipy-dev(a)scipy.net > Subject: RE: [SciPy-dev] fft code for testing > > > > > On Sat, 31 May 2003, Chuck Harris wrote: > > > > So, when n is not a power-of-two, then at least 31 C int > comparisons are > > > required. I wonder if this is the lowest bound of #operations or > > > can we do better? > > > > Probably, but by the time we are doing 1024 point > transforms the time > > spent in checking doesn't matter, whereas for the small > numbers you can > > hardly beat the direct comparisons. > > ... which gives me an idea to factor the comparison sequence by > introducing some auxiliary tests: > > int foo(int n) > { > int ok = 1; > if (n<0x100) > if (n==0x1 || n==0x2 || n==0x4 || n==0x8 || > n==0x10 || n==0x20 || n==0x40 || n==0x80); > else ok = 0; > else if (n<0x10000) > if (n==0x100 || n==0x200 || n==0x400 || n==0x800 || > n==0x1000 || n==0x2000 || n==0x4000 || n==0x8000); > else ok = 0; > else if (n==0x10000 || n==0x20000 || n==0x40000 || n==0x80000 || > n==0x100000 || n==0x200000 || n==0x400000 || n==0x800000 || > n==0x1000000 || n==0x2000000 || n==0x4000000 || > n==0x8000000 || > n==0x10000000 || n==0x20000000 || n==0x40000000); > else > ok = 0; > return ok; > } > > and as a result, much less operations are required for random small > integers. > > It would be a nice homework to find optimal steps for > auxiliary less-tests > by taking also into account the distribution of fft sizes used in real > applications... ;-) > > Pearu Yep, that would work. Binary search would be the result of taking this all the way, and it appears that the case statement is actually treated that way by gcc. I find that when doing interactive stuff I use fft sizes 256 ... 1024, because I'm usually looking to plot the results. For actual production type stuff the sizes are in the range 4Kib ... 64Kib (fourier spectroscopy, mostly). Wonder If we should decide on a range of sizes in which the fft should be optimum? Chuck

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