matplotlib-users Mailing List for matplotlib

Sorry, didn't attach the file.
John
On Thu, 2005年09月29日 at 19:31 -0400, John Byrnes wrote:
> On Thu, 2005年09月29日 at 12:43 -0400, John Byrnes wrote:
> > around line 855 or so in axes.py
> > 
> > N = sqrt( U**2+V**2 )
> > if do_scale:
> > 	Nmax = maximum.reduce(maximum.reduce(N))
> > 	U *= (S/Nmax)
> > 	V *= (S/Nmax)
> > 	N /= Nmax
> > 
> > No provision is made for the case where N is the zero vector. 
> 
> 
> I've attached a patch for axes.py and patches.py that takes fixes the
> behavior of quiver() for zero valued vectors. I'm not sure if it breaks
> anything else.
> 
> Regards,
> 
> John
> 
> --
> John Byrnes (by...@bu...)
> Graduate Student
> Electrical Engineering
> Boston University
> 
> If you know how to spend less than you get, you have the philosopher's stone.
> 		-- Benjamin Franklin
--
John Byrnes (by...@bu...)
Graduate Student
Electrical Engineering
Boston University
The radical invents the views. When he has worn them out the conservative adopts them.
		-- Mark Twain, 'Notebook,' 1935

On Thu, 2005年09月29日 at 12:43 -0400, John Byrnes wrote:
> around line 855 or so in axes.py
>=20
> N =3D sqrt( U**2+V**2 )
> if do_scale:
> 	Nmax =3D maximum.reduce(maximum.reduce(N))
> 	U *=3D (S/Nmax)
> 	V *=3D (S/Nmax)
> 	N /=3D Nmax
>=20
> No provision is made for the case where N is the zero vector. =20
I've attached a patch for axes.py and patches.py that takes fixes the
behavior of quiver() for zero valued vectors. I'm not sure if it breaks
anything else.
Regards,
John
--
John Byrnes (by...@bu...)
Graduate Student
Electrical Engineering
Boston University
If you know how to spend less than you get, you have the philosopher's ston=
e.
		-- Benjamin Franklin

On Thu, 2005年09月29日 at 09:01 -0500, Charlie Moad wrote:
> Shouldn't quiver be able to handle zero length vectors?
> 
The way I handle this is to add an extremely small value to one of the
vectors.
i.e. 
quiver(x+1e-15,x)
This should provide a workaround.
I think the issue lies in this snippet of code in the quiver function:
around line 855 or so in axes.py
N = sqrt( U**2+V**2 )
if do_scale:
	Nmax = maximum.reduce(maximum.reduce(N))
	U *= (S/Nmax)
	V *= (S/Nmax)
	N /= Nmax
No provision is made for the case where N is the zero vector. 
Hope it helps.
John
--
John Byrnes (by...@bu...)
Graduate Student
Electrical Engineering
Boston University
The best way to cheer yourself is to try to cheer someone else up.
		-- Mark Twain

I thought this was fixed about 2 months ago.
Do you have the latest version?
Mark
From: Yannick Copin <yan...@la...>
Hi,
I have a bug when I want to turn off the tick labels on subplots where
upper limits reaches 10000: the "magnitude" string (x1e4) doesn't get
erased. Example:

Hello everyone,
Hello John,
I'm thinking about this fastplot-routine for a while now. Before hacking all
the lines.py-code I wanted to ask you about your thoughts. Just to repeate a
bit:
I changed the previously sent fastplot.py (I'll call it 'plot_points()' from
now on) a bit: Now it is possible to draw multiple markers with one call.
But all at all it looks like the version sent before.
What you John asked for, was a unification with lines.py. Taking for example
triangle_down in lines.py one can read:
 def _draw_triangle_down(self, renderer, gc, xt, yt):
 offset = 0.5*renderer.points_to_pixels(self._markersize)
 rgbFace = self._get_rgb_face()
 if self._newstyle:
 path = agg.path_storage()
 path.move_to(-offset, offset)
 path.line_to(offset, offset)
 path.line_to(0, -offset)
 path.end_poly()
 renderer.draw_markers(gc, path, rgbFace, xt, yt, self._transform)
 else:
 for (x,y) in zip(xt, yt):
 verts = ( (x-offset, y+offset),
 (x+offset, y+offset),
 (x, y-offset))
 renderer.draw_polygon(gc, rgbFace, verts)
I would like to ask you (right before I'll mess everything up ;) if all this
at least could work: 
What I would try for unification is writing the dictionary 'markerd' in
lines.py (I'd prefer it right in front of 'class Line2D' as global - but
there it isn't readable for a program later, isn't it?) and change the
functions a bit like:
 def _make_triangle_down(size):
 return reshape([[0, -size, size],
 [1, size, size],
 [1, 0, -size]], (3,3))
 def _make_x(size):
 return reshape([[0, -size, -size],
 [1, size, size],
 [0, 0, 0],
 [1, size, -size],
 [1, -size, size],
 [0, 0, 0]], (6,3))
 
and so on ...
Then I would try to let the newstyle & oldstyle ploting-method use those
functions by writing a (for all markers usable) function:
def _draw_marker(self, marker, renderer, gc, xt, yt):
 func = markerd[marker]
 verts = func(1.0*renderer.points_to_pixels(int(msize)))
 rgbFace = self._get_rgb_face()
 if self._newstyle:
 path = agg.path_storage()
 for v in verts.tolist():
 if v[0]:
 path.line_to(v[1], v[2])
 if else:
 path.move_to(v[1], v[2])
 path.end_poly()
 renderer.draw_markers(gc, path, rgbFace, xt, yt, self._transform)
 else:
 for (x,y) in zip(xt, yt):
 vertices = []
 for v in verts:
 vertices.append((x+v[1], y+v[2]))
 renderer.draw_polygon(gc, rgbFace, tuple(vertices))
 # notice: some markers are partially drawn double (e.g x)
Then the plot_points-routine would contain a differing line:
 verts = func(1.0*renderer.points_to_pixels(int(msize)))[:,1:3]
All this I already tried a bit but somehow failed (I quess mainly due to
variables not beeing defined). A way out of this would be knitting those
functions into the class Line2D (it would be pretty easy to define
everything there). But than I could have used Line2D from the beginning,
couldn't I? So - to cut the long story short - where would you (if ever) add
those new lines to the code?
Another question would be: Are those new for-loops in _draw_marker() too
annoying (in the sense of speed)? (I quess they are vital for the
_make_triangle_down()-like functions to keep their simple form so that they
can be used by plot and plot_points together.)
Best regards,
Martin
-- 
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Shouldn't quiver be able to handle zero length vectors?
x =3D zeros((2,2),typecode=3D'f')
quiver(x,x)
This yields a ZeroDivisionError.
Also, is there an easy way to do a flipy for imshow?
Thanks,
 Charlie

>>>>> "Jonathan" == Jonathan Taylor <jon...@st...> writes:
 Jonathan> hi all, figured out the answer to my last post after
 Jonathan> all. apologies.
Please share :-) Even though you may now think it is obvious, it is
still not obvious to many people. A post or a wiki entry would be
much obliged.
Thanks,
JDH

hi all,
figured out the answer to my last post after all. apologies.
jonathan
-- 
Jonathan Taylor Tel: 650.723.9230
Dept. of Statistics Fax: 650.725.8977
Sequoia Hall, 137 www-stat.stanford.edu/~jtaylo
390 Serra Mall
Stanford, CA 94305 

hi all,
i have an application for which i want to use imshow to display an image
that is not very square (91x109 aspect ratio). one way to do it would be
to place it as close to the middle as possible (having different border
widths in x and y scale), but i prefer to put an even border around the
entire image. i can't seem to figure out how to automatically resize the
plotting window.
any suggestions?
thanks,
jonathan 
-- 
Jonathan Taylor Tel: 650.723.9230
Dept. of Statistics Fax: 650.725.8977
Sequoia Hall, 137 www-stat.stanford.edu/~jtaylo
390 Serra Mall
Stanford, CA 94305