matplotlib-users Mailing List for matplotlib

hi all,
i'm trying to do something extremely simple, namely print a scatter plot of
two random arrays:
import matplotlib.plt as plt
from numpy.random import *
x = rand(1,10)
scatter(x, x)
this fails with the error:
ValueError: Offsets array must be Nx2
what is happening here? are arrays somehow weird? do they not behave like
lists? any info on this will be greatly appreciated.
thank you.

I am using matplotlib-0.98.5.2 and getting a strange crash when trying to show() a window with semilog or log-log axes. Here is a simple script that will cause the crash:
import pylab
from numpy import *
x = arange(1., 10., 0.1)
y = x**2
pylab.semilogx(x,y)
pylab.show()
At the end of this message is a sample of the output. I had to cut it down because it's apparently stuck in a loop in pyparsing.py and keeps outputting the same repetitive message. Did I find a bug here? Any suggestions would be appreciated.
 Craig
Sample output:
------------------------------------------------------
 File "//usr/lib/python2.4/site-packages/matplotlib/backends/backend_gtk.py", line 352, in expose_event
 self._render_figure(self._pixmap, w, h)
 File "//usr/lib/python2.4/site-packages/matplotlib/backends/backend_gtkagg.py", line 75, in _render_figure
 FigureCanvasAgg.draw(self)
 File "//usr/lib/python2.4/site-packages/matplotlib/backends/backend_agg.py", line 279, in draw
 self.figure.draw(self.renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/figure.py", line 772, in draw
 for a in self.axes: a.draw(renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/axes.py", line 1601, in draw
 a.draw(renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/axis.py", line 710, in draw
 tick.draw(renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/axis.py", line 193, in draw
 self.label1.draw(renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/text.py", line 452, in draw
 bbox, info = self._get_layout(renderer)
 File "//usr/lib/python2.4/site-packages/matplotlib/text.py", line 252, in _get_layout
 w, h, d = renderer.get_text_width_height_descent(
 File "//usr/lib/python2.4/site-packages/matplotlib/backends/backend_agg.py", line 152, in get_text_width_height_descent
 ox, oy, width, height, descent, fonts, used_characters = \
 File "//usr/lib/python2.4/site-packages/matplotlib/mathtext.py", line 2808, in parse
 box = self._parser.parse(s, font_output, fontsize, dpi)
 File "//usr/lib/python2.4/site-packages/matplotlib/mathtext.py", line 2259, in parse
 self._expression.parseString(s)
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 1065, in parseString
 loc, tokens = self._parse( instring, 0 )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
 loc,tokens = self.parseImpl( instring, preloc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2577, in parseImpl
 return self.expr._parse( instring, loc, doActions, callPreParse=False )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
 loc,tokens = self.parseImpl( instring, preloc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2325, in parseImpl
 loc, exprtokens = e._parse( instring, loc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
 loc,tokens = self.parseImpl( instring, preloc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2690, in parseImpl
 loc, tokens = self.expr._parse( instring, loc, doActions, callPreParse=False )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
 loc,tokens = self.parseImpl( instring, preloc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2325, in parseImpl
 loc, exprtokens = e._parse( instring, loc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
------------- snip -------------
File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2309, in parseImpl
 loc, resultlist = self.exprs[0]._parse( instring, loc, doActions, callPreParse=False )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 998, in _parseCache
 value = self._parseNoCache( instring, loc, doActions, callPreParse )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 941, in _parseNoCache
 loc,tokens = self.parseImpl( instring, preloc, doActions )
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 2321, in parseImpl
 raise ParseSyntaxException(pe)
 File "/usr/lib/python2.4/site-packages/pyparsing.py", line 230, in __init__
 super(ParseSyntaxException, self).__init__(
TypeError: super() argument 1 must be type, not classobj
 

Hello list,
I'm completely new to matplotlib and I'm not a computer scientist (not
a good starting point!) but I need to solve a geometric/graphical
problem.
I've been asked to find a method, in Python, to find the distance
between a 2D polynomial curve, derived from least squares
interpolation on a set of points, and a curve locallly interpolating
another set of points.
 - the starting line is a smooth line, while the second should
describe a path passing exactly thorugh the given points.
 - the distance should be the one along the normal to the first line
I attach a sketch to explain this.
Is there an heuristic, an algorithm, to solve this problem in an
efficient way (I have to apply it to thousands couples of sets from
sonar and seismic acquisitions)? Is the mapltolip API useful for this?
Thanks in advance,
Giovanni

Afshin Eskandari <a_e...@ya...> writes:
> I upgraded my OS from fedora 6 to fedora 10. everything seems ok
> except for that when I save a figure in eps format, the quality of the
> resulting figure is poor and the size in also smaller than what it is
> supposed to be.
Just a guess: I think the default dpi value changed quite some time ago.
Does e.g. savefig('foo.eps', dpi=300) create a better-quality, larger
file?
-- 
Jouni K. Seppänen
http://www.iki.fi/jks