[Matplotlib-users] Possible bug (or unclear docs) with quiver

2012-09-27 Thread Sergio
Hi,

trying to create a velocity plot for a 2d ode and superimposing it onto
a trajectory, I am encountering some issues with quiver.

Let ns1(x,t) be a vector function defining the ode, ready to be integrated with
scipy odeint and actually invariant with t. Here, x is a 1d state array with 2
entries.

I get the velocity field by first creating vectors of interesting points on the
two axis, say xg and yg. Then I make a grid with

xxg, yyg = np.meshgrid(xg, yg)

and I finally compute the velocity components as

vel = np.asarray(map(lambda x1, x2: ns1((x1,x2),0), xxg.flat, yyg.flat))
u=vel[:,0]
v=vel[:,1]

Now, I try to superimpose a trajectory with the velocity plot.
However, after having plotted the integrated trajectory, I cannot call

plt.quiver(xxg, yyg, u, v)

because the u and v components have very different ranges.

Trying to normalize as

plt.quiver(xxg, yyg, u/xrange, v/yrange)

looks (almost) right, but it is not nice to have to precompute the ranges.

I was expecting

plt.quiver(xxg, yyg, u, v, angles='xy')

to do the job automatically, but this is not the case.
For points with null x coordinate my arrows always have null length,
while this was not the case with the previous test.

any clue?


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[Matplotlib-users] Filled Curves

2006-12-26 Thread Sergio Drumond Ventura

Hi,

I am a new user of matplotlib.
First of all I would like to say that the people working on matplotlib is
doing a great job.

Well, I have tried to use the 'fill', but I cannot get rid of the lines.
I have tried to use 'linewidth=0' at the end, but it did not work.

Could somebody, please, tell me if I am doing something wrong ?

Thank you.
Sergio.

--

#!/usr/bin/env python

from pylab import *
from matplotlib.patches import Polygon

t = arange(0.0, 1.0+0.01, 0.01)
s1 = t
s2 = t*t
s3 = t*t*t

text(0.50, 0.4,
r"$d(f_2,f_3)$", horizontalalignment='center',
color= '#8f0100', fontsize=30)

xticks(size=20)
yticks(size=20)

fill(t, s3, '#e9ccce', linewidth=0)
fill(t, s2, 'w', linewidth=0)

savefig('diamxn2.eps')
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[Matplotlib-users] Filled Curves

2006-12-16 Thread Sergio Drumond Ventura

Hi,

I am a new user of matplotlib.
First of all I would like to say that the people working on matplotlib is
doing a great job.

Well, I have tried to use the 'fill', but I cannot get rid of the lines.
I have tried to use 'linewidth=0' at the end, but it did not work.

Could somebody, please, tell me if I am doing something wrong ?

Thank you.
Sergio.

--

#!/usr/bin/env python

from pylab import *
from matplotlib.patches import Polygon

t = arange(0.0, 1.0+0.01, 0.01)
s1 = t
s2 = t*t
s3 = t*t*t

text(0.50, 0.4,
r"$d(f_2,f_3)$", horizontalalignment='center',
color= '#8f0100', fontsize=30)

xticks(size=20)
yticks(size=20)

fill(t, s3, '#e9ccce', linewidth=0)
fill(t, s2, 'w', linewidth=0)

savefig('diamxn2.eps')
-
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Join SourceForge.net's Techsay panel and you'll get the chance to share your
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