dynamic colorbar

a1.imshow(z,cmap=cm.bone,extent=(0,1,0,1))

    > does not define a mappable image that colorbar can
    > locate. This will work:

    > axes(a1) imshow(z,cmap=cm.bone,extent=(0,1,0,1)).

Yes, currently the pylab interface manipulates the current mappable
and colorbar is a pylab only construct. These features are slated to
be ported into the object interface, where the current mappable will
likely be a figure property and the colorbar will be a figure method.

Glad you found the workaround for the time being...

JDH