Changeset 4aaf89a in sasmodels for sasmodels/models/triaxial_ellipsoid.py

Timestamp:

Apr 6, 2017 4:11:41 AM (7 years ago)

Author:

Paul Kienzle <pkienzle@…>

Branches:

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

Children:

15a90c1

Parents:

b6e0636

Message:

triaxial ellipsoid/parallelepiped: choose the pair of lengths that are closest to each other as the equatorial plane when computing ER

File:

• sasmodels/models/triaxial_ellipsoid.py (modified) (2 diffs)

sasmodels/models/triaxial_ellipsoid.py

@@ -147 +147 @@
 def ER(radius_equat_minor, radius_equat_major, radius_polar):
     """
-        Returns the effective radius used in the S*P calculation
+    Returns the effective radius used in the S*P calculation
     """
     import numpy as np
     from .ellipsoid import ER as ellipsoid_ER
-     # now that radii can be in any size order, radii need sorting a,b,c where a~b and c is either much smaller or much larger
-     # also need some unit tests!
-    
-    return ellipsoid_ER(radius_polar, np.sqrt(radius_equat_minor * radius_equat_major))
+
+    # now that radii can be in any size order, radii need sorting a,b,c where a~b and c is either much smaller 
+    # or much larger
+    radii = np.vstack((radius_equat_major, radius_equat_minor, radius_polar))
+    radii = np.sort(radii, axis=0)
+    selector = (radii[1] - radii[0]) > (radii[2] - radii[1])
+    polar = np.where(selector, radii[0], radii[2])
+    equatorial = np.sqrt(np.where(~selector, radii[0]*radii[1], radii[1]*radii[2]))
+    return ellipsoid_ER(polar, equatorial)
 
 demo = dict(scale=1, background=0,
@@ -166 +171 @@
             phi_pd=15, phi_pd_n=1,
             psi_pd=15, psi_pd_n=1)
+
+# TODO: need some unit tests!