AssertionError while setting assumption after creating Matplotlib figure

[Daniel Ingraham]

Hi Sage people!

I've run into a strange problem with using Sage and Matplotlib: Sage throws an AssertionError while making an assumption about a Sage variable, but only after I create a Matplotlib figure. I've attached a short script that trips the bug when I run it with the `sage` command from the terminal.

My setup: up-to-date 64-bit Arch Linux with the sage-mathematics package from the official Arch repositories (Sage Version 6.5, Release Date: 2015-02-17).

Thanks for any help you can give!

Daniel

[Daniel Ingraham]

I forgot to attach the traceback. Added it to this post.