pcolor does not handle non-array C data

reported via VisTrails/VisTrails#1132

may be a regression from 1.3 series, reported against 1.4.3, verified against master. Not sure what last version it work on was.

import matplotlib.pyplot as plt
import numpy as np

def func3(x, ):
    return (1 - x/2 + x**5 + y**3) * np.exp(-x**2 - y**2)


# make these smaller to increase the resolution
dx, dy = 0.05, 0.05

x = np.arange(-3.0, 3.0001, dx)
y = np.arange(-3.0, 3.0001, dy)
X, Y = np.meshgrid(x, y)

Z = func3(X, Y)

# fails
plt.pcolor(X, Y, list(Z))
# plt.pcolor(X, Y, Z)  # works

Problem is in lib/matplotlib/axes/_axes.py:4969 in _pcolorargs(). It
assumes that the C argument has the .shape attribute.

        if len(args) == 1:
            C = args[0]
            numRows, numCols = C.shape
            if allmatch:
                X, Y = np.meshgrid(np.arange(numCols), np.arange(numRows))
            else:
                X, Y = np.meshgrid(np.arange(numCols + 1),
                                   np.arange(numRows + 1))
            return X, Y, C

        if len(args) == 3:
            X, Y, C = args
            numRows, numCols = C.shape
        else:
            raise TypeError(
                'Illegal arguments to %s; see help(%s)' % (funcname,
funcname))

Should be pretty straight-forward to just slap on a C = np.asanyarray(C)
before trying to access its shape.

On Wed, Oct 7, 2015 at 2:26 PM, Thomas A Caswell notifications@github.com
wrote:

reported via VisTrails/VisTrails#1132
VisTrails/VisTrails#1132

may be a regression from 1.3 series.

import matplotlib.pyplot as pltimport numpy as np
def func3(x, ):
return (1 - x/2 + x5 + y3) * np.exp(-x2 - y2)

make these smaller to increase the resolution

dx, dy = 0.05, 0.05

x = np.arange(-3.0, 3.0001, dx)
y = np.arange(-3.0, 3.0001, dy)
X, Y = np.meshgrid(x, y)

Z = func3(X, Y)

fails

plt.pcolor(X, Y, list(Z))# plt.pcolor(X, Y, Z) # works

—
Reply to this email directly or view it on GitHub
#5205.

@dopplershift

We might need to do something similar for X and Y, but I know that might
have issues with units. Didn't @dopplershift come up with a cbook function
that is like asanyarray, but safer?

On Wed, Oct 7, 2015 at 2:35 PM, Benjamin Root ben.v.root@gmail.com wrote:

Problem is in lib/matplotlib/axes/_axes.py:4969 in _pcolorargs(). It
assumes that the C argument has the .shape attribute.
        if len(args) == 1:
            C = args[0]
            numRows, numCols = C.shape
            if allmatch:
                X, Y = np.meshgrid(np.arange(numCols), np.arange(numRows))
            else:
                X, Y = np.meshgrid(np.arange(numCols + 1),
                                   np.arange(numRows + 1))
            return X, Y, C

        if len(args) == 3:
            X, Y, C = args
            numRows, numCols = C.shape
        else:
            raise TypeError(
                'Illegal arguments to %s; see help(%s)' % (funcname,
funcname))
Should be pretty straight-forward to just slap on a C = np.asanyarray(C)
before trying to access its shape.

On Wed, Oct 7, 2015 at 2:26 PM, Thomas A Caswell <notifications@github.com

wrote:

reported via VisTrails/VisTrails#1132
VisTrails/VisTrails#1132

may be a regression from 1.3 series.

import matplotlib.pyplot as pltimport numpy as np
def func3(x, ):
return (1 - x/2 + x5 + y3) * np.exp(-x2 - y2)

make these smaller to increase the resolution

dx, dy = 0.05, 0.05

x = np.arange(-3.0, 3.0001, dx)
y = np.arange(-3.0, 3.0001, dy)
X, Y = np.meshgrid(x, y)

Z = func3(X, Y)

fails

plt.pcolor(X, Y, list(Z))# plt.pcolor(X, Y, Z) # works

—
Reply to this email directly or view it on GitHub
#5205.

I made a stand-in for atleast_1d(), since it doesn't preserve subclasses; asanyarray() doesn't have that problem.

fails

plt.pcolor(X, Y,list(Z))

I don't see why one should expect the above to work. Pcolor and
similar functions are in displaying 2-D, so Z fundamentally has to be 2-D.

I would close this as not a bug.

plt.pcolor(X, Y, Z) # works

@efiring

@efiring, it is a list of 1-D numpy arrays. Applying asanyarray() would
convert it into a 2D numpy array. I am just about done with a PR to fix
this.

On Wed, Oct 7, 2015 at 2:50 PM, Eric Firing notifications@github.com
wrote:

fails

plt.pcolor(X, Y,list(Z))

I don't see why one should expect the above to work. Pcolor and
similar functions are in displaying 2-D, so Z fundamentally has to be 2-D.

I would close this as not a bug.

plt.pcolor(X, Y, Z) # works

—
Reply to this email directly or view it on GitHub
#5205 (comment)
.

Fixed by #5206, I think.

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pcolor does not handle non-array C data #5205

make these smaller to increase the resolution

fails

make these smaller to increase the resolution

fails

fails

plt.pcolor(X, Y, Z) # works

fails

plt.pcolor(X, Y, Z) # works

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pcolor does not handle non-array C data #5205

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WeatherGod commented on Oct 7, 2015

make these smaller to increase the resolution

fails

WeatherGod commented on Oct 7, 2015

make these smaller to increase the resolution

fails

dopplershift commented on Oct 7, 2015

efiring commented on Oct 7, 2015

fails

plt.pcolor(X, Y, Z) # works

WeatherGod commented on Oct 7, 2015

fails

plt.pcolor(X, Y, Z) # works

QuLogic commented on Dec 3, 2015

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