In using the function griddata in mlab.py, I think I have found a bug. The following line in mlab.py errors for me.
I supply it an xi and yi that have shape (N,1). I have surface data, but I only care about the variation in one direction. In mlab, when it gets to this line (2956 in svn revision 7040):
if min(xo[1:]-xo[0:-1]) < 0 or min(yo[1:]-yo[0:-1]) < 0:
raise ValueError, 'output grid defined by xi,yi must be monotone increasing'
the result is an error. That is, I get the following:
ValueError: min() arg is an empty sequence
A couple of things. First, if I make my variation in x to be 2 points (x = 0 for the case I'm interested in--so I just have both values of x be zero), I do not get this error and I believe the result works. So, it seems that there should be some handling of the case that there are only 1 point in either x or y direction.
Second, is it better to use the builtin python function min, or should numpy.min be used instead?