Changeset c9fc873 in sasmodels

Timestamp:

Jul 9, 2018 7:13:35 AM (6 years ago)

Author:

Torin Cooper-Bennun <torin.cooper-bennun@…>

Branches:

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

Children:

c11d09f

Parents:

751da81

Message:

normalise R_g in guinier docs; use 'SLD centre of mass'

File:

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

sasmodels/models/guinier.py

@@ -22 +22 @@
 In scattering, the radius of gyration $R_g$ quantifies the objects's
 distribution of SLD (not mass density, as in mechanics) from the objects's
-centre of mass. It is defined by
+SLD centre of mass. It is defined by
 
-.. math:: R_g^2 = \sum_i^\text{all points}\rho_i\left(r_i-r_0\right)^2
+.. math:: R_g^2 = \frac{\sum_i\rho_i\left(r_i-r_0\right)^2}{\sum_i\rho_i}
 
-where $r_0$ denotes the object's centre of mass and $\rho_i$ is the SLD at a
-point $i$.
+where $r_0$ denotes the object's SLD centre of mass and $\rho_i$ is the SLD at
+a point $i$.
 
 Notice that $R_g^2$ may be negative (since SLD can be negative), which happens