Mailman 3 August 2002 - SciPy-User

Parameter estimation / Data fitting in scipy
by Nils Wagner 17 Sep '02

17 Sep '02

Hi, Suppose it is desired to fit a set of data y_i to a known model [given in form of an IVP (initial value problem)] y' = f(y,p,t) , y(0) = y_0(p), y' = dy/dt where p is a vector of parameters for the model that need to be found. y denotes the state-variables. The initial conditions y(0) may also depend on parameters. How can I solve this problem using scipy's optimization and ode tools ? A small example would be appreciated. Thanks in advance Nils

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Reliability of linalg.eig for complex matrices A,B
by My VDI Freemail 30 Aug '02

30 Aug '02

Hi, I tried to solve a transcendental eigenvalue problem with scipy. However It works more or less for r e a l arguments x, but for complex arguments I cannot observe convergency to any eigenvalue. I guess its a problem of the eigenvalue solver. Please find attached my small example. Any ideas or suggestions ? Nils

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Error calculation in signals ...
by Andrew P. Lentvorski 29 Aug '02

29 Aug '02

I have a question concerning how to calculate error in two signals. Consider a two voltage signals vs. time. Both of these signals are roughly sinusoidal and can be described by a series of (time, voltage) pairs (or vectors, converting is easy). How do I calculate the error in *time*? Calculating the voltage error between the two is reasonable. Add interpolated time points to voltage1 such that it has signals at all voltage2 time points and vice versa. Now you have two signal vectors which have the same time points. Calculate your favorite error measure and enjoy. Suggestions as to how to do this *quickly* are welcomed. However, now I want to calculate the time error between the two signals. These are both sinusoids which are pretty close to the same signal, but not quite (one is from a later cycle and has a bit of noise). How do I calculate the time error for each sample? I could simply run a loop over each sample, find the two nearest bracketing points in voltage on the other signal, and then interpolate to find the time. But that's going to take a *long* time. Is there a faster/more mathematical way to do this? Thanks, -a

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weave and compilers other than GCC 2.95?
by Steve M. Robbins 27 Aug '02

27 Aug '02

Hullo, Since July (when a discussion here alerted me to it) I've been happily using weave to speed up some loops in my code. I was developing under Debian linux which uses GCC 2.95.4 as the default compiler. I finally managed to get scipy built on our IRIX system the other day, and tried to run my code there. Sadly, the IRIX compiler balked at the weave-produced code. I got a number of errors of the type #error directive: This header file requires the -LANG:std option I realize that weave.inline() lets you specify extra compiler args, but that's a little tedious for system-dependent flags like this. Just where does the compiler definition come from, anyway? Is there a global way to set it, e.g. using environment args or a config file? OK, so as a test, I set -LANG:std using extra_compile_args. Now I have 48 errors instead of 10! Most of the errors are of the following kind. A type specifier is expected. template <class T> bool operator==(const SeqBase<T>::iterator& left, const SeqBase<T>::iterator& right); ^ In addition there are "cout undeclared" errors. So I'm left scratching my head. Has weave never before been tested with the IRIX compiler? Or am I doing something stupid? I'm using weave checked out with the scipy CVS tree. Is that current? Python is 2.1.3 with Numeric 21. Now that I have the weave-produced code in a file in ~/.python21_compiled, I tried it with other compilers available. None of my GCC 3.0.x nor GCC 3.1 nor GCC 3.2 would compile the file either! Neither under IRIX nor under Linux. Besides some warnings about "antiquated headers" :-) there are errors like the following ....scipy/weave/CXX/Objects.hxx:1143: no class template named `random_access_iterator' in `std' as well as "cout undeclared". These errors sound like they can be cured by #including the right mix of headers. Is there a patch already available for this? Thanks, -Steve P.S. I'm testing weave, by the way, using Fernando Perez's examples. On Mon, Jul 22, 2002 at 08:55:15PM -0600, Fernando Perez wrote: > > I've posted an updated version of my weave examples with this at: > > http://www-hep.colorado.edu/~fperez/python/python-c/weave_examples.html > > http://www-hep.colorado.edu/~fperez/python/python-c/weave_examples.py > > One is color highlighted, the other pure text for python use.

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Start time for SciPy workshop
by Richard Henchman 26 Aug '02

26 Aug '02

Would you please let me know at what time the SciPy workshop starts? I saw the web page http://www.scipy.org/site_content/scipy02/scipy02_agenda.htm has the agenda but no specific times. We're considering driving up in the morning instead of staying overnight on Wednesday and would like to know if this is feasible. Thanks, Richard

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Please confirm your request to join FlyLadyMentors
by Yahoo!Groups 25 Aug '02

25 Aug '02

Hello scipy-user(a)scipy.net, We have received your request to join the FlyLadyMentors group hosted by Yahoo! Groups, a free, easy-to-use community service. This request will expire in 21 days. TO BECOME A MEMBER OF THE GROUP: 1) Go to the Yahoo! Groups site by clicking on this link: http://groups.yahoo.com/i?i=UsRPi77NUR2r5XyvwTZbohPSDgs&e=scipy-user%40scip… (If clicking doesn't work, "Cut" and "Paste" the line above into your Web browser's address bar.) -OR- 2) REPLY to this email by clicking "Reply" and then "Send" in your email program If you did not request, or do not want, a membership in the FlyLadyMentors group, please accept our apologies and ignore this message. Regards, Yahoo! Groups Customer Care Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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xplt
by Jochen Küpper 22 Aug '02

22 Aug '02

Scipy cvs gives me the following error ,---- | Python 2.2.1 (#2, Aug 16 2002, 10:34:47) | [GCC 3.2] on linux2 | Type "help", "copyright", "credits" or "license" for more information. | >>> import scipy | Traceback (most recent call last): | File "<stdin>", line 1, in ? | File "/usr/local/lib/python2.2/site-packages/scipy/__init__.py", line 68, in ? | import xplt | File "/usr/local/lib/python2.2/site-packages/scipy/xplt/__init__.py", line 31, in ? | from Mplot import * | File "/usr/local/lib/python2.2/site-packages/scipy/xplt/Mplot.py", line 878, in ? | import colorbar | File "/usr/local/lib/python2.2/site-packages/scipy/xplt/colorbar.py", line 9, in ? | from slice3 import * | File "/usr/local/lib/python2.2/site-packages/scipy/xplt/slice3.py", line 1466, in ? | _poly_permutations4 = _construct3 (0) | File "/usr/local/lib/python2.2/site-packages/scipy/xplt/slice3.py", line 1460, in _construct3 | mask = find_mask (below, _node_edges3 [itype]) | TypeError: Array can not be safely cast to required type `---- This happens for a while already, but I had xplt excluded from the import a while ago and then forgot about it... I couldn't find anything usefull in the ml archives, they only came up with many false hits. Any ideas? Greetings, Jochen -- University of North Carolina phone: +1-919-962-4403 Department of Chemistry phone: +1-919-962-1579 Venable Hall CB#3290 (Kenan C148) fax: +1-919-843-6041 Chapel Hill, NC 27599, USA GnuPG key: 44BCCD8E

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Resultant of two polynomials - Sylvester matrix.
by Nils Wagner 21 Aug '02

21 Aug '02

Hi, I am looking for a function which computes the resultant of two polynomials. It is defined to be the determinant of their Sylvester matrix. A small example would be appreciated. Thanks in advance. Nils

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clapack--installation problem
by Giovanni Montana 20 Aug '02

20 Aug '02

Hello I am trying to get SciPy installed in my linux box. I got the last version via CVS, and have installed f2py2e, ATLAS, and Numeric. All seems OK, but when I import scipy from Python, I get "exceptions.ImportError: No module named clapack". My guess is that I should change scipy/scipy_distutils/site.cfg to tell scipy where to find the lapack library, but it doesn't work. Any idea? I need to get scipy work as soon as possible, so any help will be greately appreciated! Thank you. Giovanni PS: By the way, do you also know where to find another implementation of the gamma function for Python?

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SciPy build system
by Tom Harris 18 Aug '02

18 Aug '02

Greetings, This may seem an odd request but is the SciPy build system available anywhere? I am currently researching build scoreboard systems and have failed to see anything usable for my situation and written in Python. I am really interested in the bit that collates the results from multiple builds / test suites and presents them. Tom Harris, Software Engineer Optiscan Imaging, 15-17 Normanby Rd, Notting Hill, Melbourne, Vic 3168, Australia email tomh(a)optiscan.com ph +61 3 9538 3333 fax +61 3 9562 7742 This email may contain confidential information. If you have received this email in error, please delete it immediately,and inform us of the mistake by return email. Any form of reproduction, or further dissemination of this email is strictly prohibited. Also, please note that opinions expressed in this email are those of the author, and are not necessarily those of Optiscan Pty Ltd.

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