Re: [Matplotlib-users] Artefacts in contour plot?

[Dominique O. <Dom...@po...>]

Nadia Dencheva wrote:
> I've been able to reproduce the problem on MacOSX (after the 
> correction), although I don't have an answer to what's causing it now.

Results seem inconsistent; if i replace the 'rosenbrock' function in my 
previous script with

   def saddle(x,y): return y**2 - x**2

and use

   x = y = arange( -2, 2, 0.1 )

then

   contour( Z, x = X, y = Y, levels = 30, origin = 'lower' )

produces the zigzags, but

   contour( Z, x = X, y = Y, levels = 30, origin = 'upper' )

doesn't. The same isn't true of the rosenbrock function. I wonder if the 
zigzags might be coming from the C function which computes the levels. 
Is there a C interface to that function somewhere that we could try?

Dominique