[feature] gridding utils

[pc494]

#89 but to the correct branch.

As detailed elsewhere #84 we're porting (some) of the gridding functionality from diffsims to orix. I will also bump the matplotlib version in setup.py.

Release Notes:
orix can now produce uniform grids of rotations around a fixed rotations, or within a stated fundamental zone.

Notes:
This will close #85

[dnjohnstone]

Will this address #86 also?

[pc494]

#86 is going back to diffsims I think, as I'm not doing stereographic projection stuff in orix (but need a few of the utils that I had made - in diffsims- for the ZAP map generator).

[dnjohnstone]

#86 is going back to diffsims I think, as I'm not doing stereographic projection stuff in orix (but need a few of the utils that I had made - in diffsims- for the ZAP map generator).

Ok - when this one is done, I think maybe we should remove the stereographic_projection stuff from diffsims, i.e. still get rid of all the gridding stuff from there, since we can use this fundamental zone stuff instead and just leave the issue in orix as "for the future" functionality. Does that sound ok?

[pc494]

Yep, just wanted to do it carefully so as not to break the zap map code. Normal template matching should be done with fundamental zone grids.

[pc494]

I think I have found the bug, if the samples created post 6495611 are still uniform (according to MTEX) I think they will have a sensible number of n ~ 161 914 / 2 (if you could check that would be must appreciated @hakonanes)

Assuming that has worked I would hope to wrap this (and my review of #92) early next week which puts us in a good place wrt v0.4

[hakonanes]

Pulling the recent changes and sampling point group 32 with get_sample_fundamental(2.273, Oh) I get 83 693 orientations. The ODF computed with MTEX with default parameters has texture index 1.0084, entropy -0.0046 and max intensity 1.1160. Before 6495611, these four numbers were 161 914 1.0028, -0.0016, 1.0406.

The number of orientations is halfed, while the sampling seems to retain most of its uniformity!

[hakonanes]

Plotting 10 000 random orientations from the samples with MTEX:

Orix (83 693 orientations)	EMsoft (72 227)	MTEX (54514)

[hakonanes]

I would just like to note that I hope we (I) can implement the orientation sampling procedure from EMsoft as well... Most likely as part of a later release, as my hack included above requires multiple optimizations and generalising to all crystal systems.

[pc494]

Okay, my feelings are:

• I can tidy this up to something that we can merge, with functionality as is
• The different number of orientations is due to ambiguous definitions of "resolution"
• The function uniform_sample_SO3 could easily have a kwarg added in a future release for other methods (eg EMsoft's method)

I propose that I perform the tidy up here and get it merged, and I'll raise a new issue to cover the latter two bullet points.

[hakonanes]

I propose that I perform the tidy up here and get it merged, and I'll raise a new issue to cover the latter two bullet points.

Sounds good.

[pc494]

This is now ready to review :)

[hakonanes]

Minor docstring comments, looks good to go otherwise.

[pc494]

I think this is good to go now

[hakonanes]

I took (for the first time) the liberty of merging... If you guys @pc494 @dnjohnstone want that task to continue to be your responsibility alone, I understand that.

[pc494]

Nope that's great, it means I can cross "figure out how to get @hakonanes made an admin on orix" off my list!

[dnjohnstone]

I took (for the first time) the liberty of merging... If you guys @pc494 @dnjohnstone want that task to continue to be your responsibility alone, I understand that.

Absolutely great @hakonanes ! I think you've got more claim to that than me these days!

[hakonanes]

Glad to hear it, thanks a lot!