[Matplotlib-users] problem loglog plots with errorbars?

[Istvan S. <szapudi@IfA.Hawaii.Edu>]

Hi All,

I am fairly new to matplotlib, and I am impressed with its
capabilities.

I have trouble plotting loglog plots with errorbars. I have
the following, program, a slightly modified version of one
given earlier by JDH on 9-28-2004 in this mailing list:
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from matplotlib.matlab import *
import random

random.seed(13)
## with 10 elements it works
## but with 11 elements it crashes
x = arange(1.0,12)
y = array(map(lambda s:1e6*random.random()+1e5+1,x))
err = array(map(lambda s:1e5*random.random(),x))

print x,y,err
print y-err
ax = gca()
errorbar(x,y,err,fmt='o')
##plot(x,y)
ax.set_yscale("log")
ax.set_xscale("log")
show()
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The weird thing is that it runs with 10 points, but not
with 11 or more. I guess the random generator happens to generate
a configuration which breaks the routine. I did check
that everything is positive (BTW, it would be great to have
a version which simply ignores negative/0 values), the last
point does not seem special, I can't figure out what's going on.

I run matplotlib 0.64 (sorry I did not convert to pylab yet),
on python 2.3.4/gcc 3.3.1 under a fairly new cygwin installation in
WinXP SP2.

any clue anybody?

thanks, I.
ps. Merry Xmas/Happy Holidays to everybody!
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Istvan Szapudi
Institute for Astronomy
University of Hawaii
2680 Woodlawn Drive
Honolulu, HI 96822
USA
Tel. :  (808) 956-6196 (also x9844 in Febr/March)
Fax  :  (808) 956-9590
Email: sz...@if...
WWW  : http://www.ifa.hawaii.edu/~szapudi/istvan.html
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