Assembly Rotation Cleanup

[albeanth]

There several rotation methods:

1. armi/armi/reactor/assemblies.py

   Line 1215 in 7e1e167

   def rotate(self, rad):

2. armi/armi/reactor/assemblies.py

   Line 312 in 7e1e167

   def rotatePins(self, *args, **kwargs):

3. armi/armi/reactor/blocks.py

   Line 1827 in 7e1e167

   def rotate(self, rad):

4. armi/armi/reactor/blocks.py

   Line 1902 in 7e1e167

   def rotatePins(self, rotNum, justCompute=False):

5. armi/armi/physics/fuelCycle/assemblyRotationAlgorithms.py

   Line 76 in 7e1e167

   def simpleAssemblyRotation(fh):

It looks like they all boil down to the two methods on blocks.py, rotate and rotatePins. The docstring for rotatePins suggests that calling it on it's own does not constitute rotation.

armi/armi/reactor/blocks.py

Lines 1928 to 1932 in 7e1e167

	Notes
	-----
	Changing (x,y) positions of pins does NOT constitute rotation, because the indexing of pin
	atom densities must be re-ordered. Re-order indexing of pin-level quantities, NOT (x,y)
	locations of pins. Otherwise, subchannel input will be in wrong order.

That said, I think we should consider making rotatePins private and/or putting warnings in docstrings (on that method, assembly.rotatePins, and assemblyRotationAlgorithms.py::simpleAssemblyRotation) saying that it's an incomplete rotation.

[albeanth]

Additionally, rotatePins is fixed to increments of 60 degree rotations, while rotate is expected to be a flexible rotation. However, once assembly.rotate boils down to blocks.rotate, that flexible rotation angle needs to be in 60 degree increments

armi/armi/reactor/blocks.py

Lines 1839 to 1844 in 7e1e167

	Parameters
	----------
	rad: float, required
	Angle of counter-clockwise rotation in units of radians. Rotations must be
	in 60-degree increments (i.e., PI/6, PI/3, PI, 2 * PI/3, 5 * PI/6,
	and 2 * PI)