Re: [IMP-users] Problem with IMP.core.TransformationSymmetry

[Ben Webb <>]

On 12/5/20 12:21 PM, Jan Kosinski wrote:
> And, I would keep your PMI fix rather than create_compatible_rigid_body. 
> The create_compatible_rigid_body 
> runs get_transformation_aligning_first_to_second so it seems to be more 
> computationally costly, am I correct Ben?.

Sure, but it's a one-time cost - I doubt you'd notice the difference.

> I could imagine things could be slightly different but here the rb 
> rotations are not different only slightly

Looks like a simple inversion to me, a very slight difference giving a 
very different result. e.g. -1e-16 and +1e-16 are only very slightly 
different but are of opposite sign.

> Maybe the create_rigid_body function 
> could use the PMI fix internally?

It's a workaround. The fix is to use create_compatible_rigid_body. You 
can certainly use the PMI workaround but then your reference frame won't 
align with the principal axes of the body, maybe not an issue in your 
application.

	Ben
--
                      https://salilab.org/~ben/
"It is a capital mistake to theorize before one has data."
	- Sir Arthur Conan Doyle