Re: [Matplotlib-users] Two bugs in quiver?

2009-01-20 Thread George Nurser 
Downloaded latest svn numpy and matplotlib and it works perfectly now.
Thanks for sorting it out so quickly.

George.

2009/1/20 Eric Firing efir...@hawaii.edu:
 George Nurser wrote:

 I think there may be two bugs in quiver.

 Actually just 1...


 1. Quiver doesn't seem to accept 1D arrays X and Y if they are
 different sizes -- they need to be turned into 2d arrays with meshgrid
 for the program to work. With line 13 uncommented I get the following
 error message:

 This is a bug.  It is fixed now in svn trunk and 98.5 maintenance branch.


 2. Masking is not working properly with quiver, while it works fine
 with contour -- see the attached quivtest.png

 This is a numpy.ma bug that has been fixed in numpy.  I don't know exactly
 when it was fixed, but after I tracked it down to numpy.ma, I updated my
 copy of numpy from svn, and the problem went away.  Somehow, when a
 multiplication was done with broadcasting, the mask was getting handled and
 propagated incorrectly.  I suspect this bug was present only for a moderate
 interval of time, because quiver with masked points worked for a long time
 before you ran into the bug.

 Eric


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[Matplotlib-users] Two bugs in quiver?

2009-01-19 Thread George Nurser 
I think there may be two bugs in quiver.

1. Quiver doesn't seem to accept 1D arrays X and Y if they are
different sizes -- they need to be turned into 2d arrays with meshgrid
for the program to work. With line 13 uncommented I get the following
error message:

  File quivtest.py, line 13, in module
ax.quiver(XT,YT,uu,vv) #fails
  File 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/axes.py,
line 5533, in quiver
q = mquiver.Quiver(self, *args, **kw)
  File 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/quiver.py,
line 343, in __init__
self.XY = np.hstack((X[:,np.newaxis], Y[:,np.newaxis]))
  File 
/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/numpy/lib/shape_base.py,
line 488, in hstack
return _nx.concatenate(map(atleast_1d,tup),1)
ValueError: array dimensions must agree except for d_0

2. Masking is not working properly with quiver, while it works fine
with contour -- see the attached quivtest.png

quiver.py:

import numpy as np
import numpy.ma as ma
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
XT = np.arange(10.)
YT = np.arange(20.)
uu = np.zeros([20,10])+7.
vv = np.zeros([20,10])+3.

fig = plt.figure()
ax = fig.add_subplot(121)
# ax.quiver(XT,YT,uu,vv) #fails
XX,YY = np.meshgrid(XT,YT)
ax.quiver(XX,YY,uu,vv) #Ok

ax = fig.add_subplot(122)
msk = XX**2+YY**2 50
uumsk = ma.masked_array(uu,mask=msk)
vvmsk = ma.masked_array(vv,mask=msk)
ax.contour(XT,YT,uumsk*XX) # works
ax.quiver(XX,YY,uumsk,vvmsk) # gives strange shapes
plt.show()
fig.savefig('quivtest.png',dpi=100)

George Nurser.
attachment: quivtest.png--
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Re: [Matplotlib-users] Two bugs in quiver?

2009-01-19 Thread Eric Firing 
George Nurser wrote:
 I think there may be two bugs in quiver.

Thanks for the report.  I can reproduce both problems, and I will try to 
solve them.

Eric

 
 1. Quiver doesn't seem to accept 1D arrays X and Y if they are
 different sizes -- they need to be turned into 2d arrays with meshgrid
 for the program to work. With line 13 uncommented I get the following
 error message:
 
   File quivtest.py, line 13, in module
 ax.quiver(XT,YT,uu,vv) #fails
   File 
 /Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/axes.py,
 line 5533, in quiver
 q = mquiver.Quiver(self, *args, **kw)
   File 
 /Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/quiver.py,
 line 343, in __init__
 self.XY = np.hstack((X[:,np.newaxis], Y[:,np.newaxis]))
   File 
 /Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/numpy/lib/shape_base.py,
 line 488, in hstack
 return _nx.concatenate(map(atleast_1d,tup),1)
 ValueError: array dimensions must agree except for d_0
 
 2. Masking is not working properly with quiver, while it works fine
 with contour -- see the attached quivtest.png
 
 quiver.py:
 
 import numpy as np
 import numpy.ma as ma
 import matplotlib
 matplotlib.use('Agg')
 import matplotlib.pyplot as plt
 XT = np.arange(10.)
 YT = np.arange(20.)
 uu = np.zeros([20,10])+7.
 vv = np.zeros([20,10])+3.
 
 fig = plt.figure()
 ax = fig.add_subplot(121)
 # ax.quiver(XT,YT,uu,vv) #fails
 XX,YY = np.meshgrid(XT,YT)
 ax.quiver(XX,YY,uu,vv) #Ok
 
 ax = fig.add_subplot(122)
 msk = XX**2+YY**2 50
 uumsk = ma.masked_array(uu,mask=msk)
 vvmsk = ma.masked_array(vv,mask=msk)
 ax.contour(XT,YT,uumsk*XX) # works
 ax.quiver(XX,YY,uumsk,vvmsk) # gives strange shapes
 plt.show()
 fig.savefig('quivtest.png',dpi=100)
 
 George Nurser.
 
 
 
 
 
 
 
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Re: [Matplotlib-users] Two bugs in quiver?

2009-01-19 Thread Eric Firing 
George Nurser wrote:
 I think there may be two bugs in quiver.

Actually just 1...

 
 1. Quiver doesn't seem to accept 1D arrays X and Y if they are
 different sizes -- they need to be turned into 2d arrays with meshgrid
 for the program to work. With line 13 uncommented I get the following
 error message:

This is a bug.  It is fixed now in svn trunk and 98.5 maintenance branch.

 
 2. Masking is not working properly with quiver, while it works fine
 with contour -- see the attached quivtest.png

This is a numpy.ma bug that has been fixed in numpy.  I don't know 
exactly when it was fixed, but after I tracked it down to numpy.ma, I 
updated my copy of numpy from svn, and the problem went away.  Somehow, 
when a multiplication was done with broadcasting, the mask was getting 
handled and propagated incorrectly.  I suspect this bug was present only 
for a moderate interval of time, because quiver with masked points 
worked for a long time before you ran into the bug.

Eric

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