Changeset 9802ab3 in sasmodels for sasmodels/models/parallelepiped.py

Timestamp:

Apr 10, 2017 11:56:55 AM (7 years ago)

Author:

richardh

Branches:

master, core_shell_microgels, costrafo411, magnetic_model, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests

Children:

69e1afc

Parents:

dedcf34

Message:

changes to docs, anticipating new orientation angle integrals

File:

• sasmodels/models/parallelepiped.py (modified) (1 diff)

sasmodels/models/parallelepiped.py

@@ -112 +112 @@
     detector plane.
 
+On introducing "Orientational Distribution" in the angles, "distribution of theta" and "distribution of phi" parameters will
+appear. These are actually rotations about axes $\delta_1$ and $\delta_2$ of the parallelepiped, perpendicular to the $a$ x $c$ and $b$ x $c$ faces. 
+(When $\theta = \phi = 0$ these are parallel to the $Y$ and $X$ axes of the instrument.) The third orientation distribution, in $\psi$, is 
+about the $c$ axis of the particle, perpendicular to the $a$ x $b$ face. Some experimentation may be required to 
+understand the 2d patterns fully. (Earlier implementations had numerical integration issues in some circumstances when orientation 
+distributions passed through 90 degrees, such situations, with very broad distributions, should still be approached with care.) 
+
+    
 For a given orientation of the parallelepiped, the 2D form factor is
 calculated as