New doc build failure

[mdboom]

Latex problems again. Doc pull requests merged in the last day are #1924 and #1918, by the looks of it.

There's a lot of warnings, ending in:

LaTeX Warning: Hyper reference `mpl_toolkits/mplot3d/index:toolkit-mplot3d-inde
x' on page 521 undefined on input line 29783.


LaTeX Warning: File `_images/contourf3d_demo21.png' not found on input line 297
88.


! Package pdftex.def Error: File `_images/contourf3d_demo21.png' not found.

See the pdftex.def package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.29788 ...graphics{_images/contourf3d_demo21.png}

? 
! Emergency stop.
 ...                                              

l.29788 ...graphics{_images/contourf3d_demo21.png}

!  ==> Fatal error occurred, no output PDF file produced!

Build log

[takluyver]

I've once again disabled the daily builds, so please ping me when you think that this has been fixed.

[mdboom]

It seems to go back to @pelson's 401e907, which introduced an image linked to the _image directory. The _image directory is created only for the HTML build, so LaTeX can't see it. Changing this to a plot directive resolves the issue [see attached], and I'm able to complete the doc build, at least on my local machine.

[pelson]

Thanks @mdboom. I'm going to merge, as this is a better solution. @takluyver - does this fix the PDF build?

[takluyver]

Yep, it seems to be working again. Thanks!