Mailman 3 April 2004 - SciPy-User

problems with stats
by danny shevitz 04 May '04

04 May '04

Howdy, I've encountered two problems with the binomial distribution in the stats module. The first is trivial and I believe just an argument checking problem. >>> binom.pdf(0,3,.5) bdtr domain error 1.#QNAN (the answer should be .125 of course) The second is a little more significant. I'm trying to invert the binomial distribution using ppf. I looked at distributions.py class binom_gen(rv_discrete): . . . def _ppf(self, q, n, pr): vals = ceil(special.bdtrik(q,n,pr)) vals1 = vals-1 temp = special.bdtr(vals1,n,pr) return where(temp >= q, vals1, vals) and ppf is in fact implemented, but when I try to run it I get an error. >>> binom.ppf(3,4,.95) Traceback (most recent call last): File "<stdin>", line 1, in ? File ".\site-packages\scipy\stats\distributions.py", line 2371, in ppf TypeError: _ppf() takes exactly 4 arguments (3 given) Does anyone know what's going on. Am I misusing something? thanks, Danny __________________________________ Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs http://hotjobs.sweepstakes.yahoo.com/careermakeover

3 6

Re: xplt documentation
by Nadav Horesh 30 Apr '04

30 Apr '04

>First you can try > help("scipy.xplt") > help("scipy.xplt.plot") >to get further information. >As xplt is based on pygist this document > http://bonsai.ims.u-tokyo.ac.jp/~mdehoon/software/python/pygist_html/pygist… >might help you further. > >You wrote that you would like to use xplt interactively - >I am not sure what you mean, e.g. the following works nicely > >In [1]: from scipy.xplt import * >In [2]: x=arange(0.0,1.0,0.1) >In [3]: plg(x*x,x) > >(the prompt is from Ipython, but the normal python will do as well, >though you'll miss all the nice features of Ipython ;-). >You can still use the mouse to zoom in and such. >To capture a mouse click you can use the mouse function of xplt. > >Hope this helps. > >Arnd > > >On Wed, 28 Apr 2004, Nadav Horesh wrote: > >> I just started to play with xplt under linux. The package seems to fill >> some of the missing features in gnuplot(gplt) 4.0. The problem I have is >> that I can not use it interactively unless I run a loop of >> xplt.pyg_pending(). Is there a "decent" way to make an interactive xplt >> session? Where can I find some useful documentation beside the plotting >> tutorial? >> >> Nadav. >> >> _______________________________________________ >> SciPy-user mailing list >> SciPy-user(a)scipy.net >> http://www.scipy.net/mailman/listinfo/scipy-user >> Thank you for the references.. The problem with the need to loop over xplt.pyg_pending(), is specific to IDLE. The problem with plt and xplt is that they don't leave happily with IDLE, which is my favorite (I have experience with with pycrust and Ipython). Is there any workaround or this is a fundamental issue of Tkinter? Nadav.

3 2

Drivers for gplt distributed with scipy?
by George B. Christianson 30 Apr '04

30 Apr '04

Greetings to all from a new user of scipy! My environment for scipy consists of a PC running Windows 2000 with Cygwin (full installation, in the last month) & its Python2.3, and scipy and f2py2e installed from the CVS repositories. Here's my question: I'm using the scipy.gplt routines to visualize some 3d data sets, and getting pretty good plots on the Xwindows terminal, but I don't appear to be able to write plots to files. For example, the fragment ... plotting commands... gplt.output(filename, 'epslatex color') gplt.close() with filename "myfile.eps" does generate a file "myfile.eps" in my working directory, which I can open with Adobe PhotoShop, but there is no graph in it. I get similar results with a png file. The documentation refers to drivers needed gnuplot -- how can I tell whether I have any installed, and how can I obtain and install them if I need to? Thanks very much in advance for any help! George Christianson

1 0

Re: [SciPy-user] matplotlib question
by Gary Ruben 29 Apr '04

29 Apr '04

A. Same as for any Python script, just give your script a .pyw extension - it works on my Win98 system. I have matplotlib configured to use the GTKAgg backend. Gary Ruben <snip> > > So this isn't a scipy question, but since it came up during a gplt > > question I'll ask anyway. > > > > I started using matplotlib for plotting my histograms and a python.exe > > shell always opens. Is there any way to get rid of this, e.g. run > > pythonw.exe instead. > > > > thanks, > > Danny -- ___________________________________________________________ Sign-up for Ads Free at Mail.com http://promo.mail.com/adsfreejump.htm

1 0

matplotlib question
by danny shevitz 29 Apr '04

29 Apr '04

So this isn't a scipy question, but since it came up during a gplt question I'll ask anyway. I started using matplotlib for plotting my histograms and a python.exe shell always opens. Is there any way to get rid of this, e.g. run pythonw.exe instead. thanks, Danny __________________________________ Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs http://hotjobs.sweepstakes.yahoo.com/careermakeover

2 1

wassup with histogram?
by danny shevitz 29 Apr '04

29 Apr '04

So I tried to use stats.histogram and I believe I found a bug, but I also have a bigger wtf with the algorithm. If I create a random vector in [0,1). I get uneven counts. Here it is: #################################################### import scipy from scipy.stats import histogram from random import random n = 100 randArray = [random() for i in range(n)] answer = histogram(randArray) print answer #################################################### gives (array([15, 17, 22, 20, 20, 6, 0, 0, 0, 0]), -0.094840236656285076, 0.20868271373704711, 0) Notice that the last entries in the histogram are all zeros. This is always the case. Also notice the bin width is about .2 which is approximately double what it should be. I have traced the error and in the stats.py module the code estbinwidth = float(Max - Min)/float(numbins) + 1 binsize = (Max-Min+estbinwidth)/float(numbins) computes the bin size incorrectly. In particular the +1 in estbinwidth needs to be in parentheses. You would only notice this for small data ranges which is perhaps why it was never noticed. Personally, I would just compute the binsize in one step as binsize = (numbins+1)(Max-Min+estbinwidth)/numbins**2. But now for the wtf part. The histogram centers the lowest and highest bins around the lowest and highest point in the data as witnessed in the code lowerreallimit = Min - binsize/2.0 and the fact that the bin size isn't just (max - min)/n. Why would you possibly want to do this? With this technique, if you histogram a sample of uniform random variates, then the outer two bins will have half the counts of the other bins because only half the bin is within range. There must be a reason for doing this, but I sure don't know what it is. D __________________________________ Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs http://hotjobs.sweepstakes.yahoo.com/careermakeover

1 0

Problem plotting with scipy 0.3
by Srinath Avadhanula 29 Apr '04

29 Apr '04

Hello, I recently downloaded scipy and tried to run the following according to the "Plotting tutorial" page on the scipy home-page: >> import gui_thread >> gui_thread.start() <wxPython imported> >> >> from scipy import plt >> plt.plot((1,2,3)) A window pops up and I get the following error: (this error in fact repeats itself infinitely on the console till I interrupt it). Traceback (most recent call last): File "C:\Python23\Lib\site-packages\scipy\plt\wxplt.py", line 143, in on_paint self.draw(wx.wxPaintDC(self)) File "C:\Python23\Lib\site-packages\scipy\plt\wxplt.py", line 424, in draw self.draw_graph_area(dc) File "C:\Python23\Lib\site-packages\scipy\plt\wxplt.py", line 379, in draw_graph_area int(gb.width()+2),int(gb.height()+2)) File "C:\Python23\Lib\site-packages\wx\gdi.py", line 2597, in SetClippingRegion return _gdi.DC_SetClippingRegion(*args, **kwargs) TypeError: DC_SetClippingRegion() takes exactly 3 arguments (5 given) The versions of the various packages I am using are: wxPython: 2.5.1.5u Numeric: 23.1 Python: 2.3 scipy: 0.3.0_265.4219 Thanks, Srinath

1 0

xplt documentation
by Nadav Horesh 28 Apr '04

28 Apr '04

I just started to play with xplt under linux. The package seems to fill some of the missing features in gnuplot(gplt) 4.0. The problem I have is that I can not use it interactively unless I run a loop of xplt.pyg_pending(). Is there a "decent" way to make an interactive xplt session? Where can I find some useful documentation beside the plotting tutorial? Nadav.

2 1

marginal distributions
by Scott Bray 28 Apr '04

28 Apr '04

1 0

no __setitem__ in spmatrix class
by pascal barbedor 27 Apr '04

27 Apr '04

Hi I noticed there is no __setitem__ method in spmatrix class in scipy.sparse module but what if one needs to (sparsely) fill the matrix after __init__ time ? thanks

3 2