Re: [Matplotlib-users] how to make matplotlib faster?

[John H. <jdh...@ac...>]

>>>>> "Norbert" == Norbert Nemec <No...@ne...> writes:

    Norbert> I have experienced some extreme inefficiency using
    Norbert> errorbar plots for large datasets. Obviously, the
    Norbert> "hlines" routine is a huge bottleneck. Would it be
    Norbert> possible, in principle, to use an efficient collection
    Norbert> instead?
As Perry noted, it would be nice to see some of Eric's code to see if
this is the kind of bottleneck he is bumping into.

It would be very straightforward to use collections here is what they
were designed for - removing bottlenecks created by instantiating many
similar objects.  I've never plotted a large number of errorbar lines
so haven't bumped into this one.

Note this might break some code which is relying on the fact that the
errorbar routing is returning a list of errorbar lines.  collections
are designed to respond similarly to lists of lines under the set
command.  Eg

  set(lines, color='r', linewidth=4)

and 

  set(collection, color='r', linewidth=4)

will both work.

But if someone is currently doing 

  lines[2].set_color('g')

or

  for line in lines:
      line.set_something(else)

there would be a backward incompatibility with this change.  Note it
would be possible to define setitem, getitem, and possibly setslice,
getslice and iter for collections to make them behave more like lists
of objects, which would be nice if we (you) want to make this change.

Is anyone changing the properties of individual error lines returned
by errorbar?

JDH