Changeset aa90015 in sasmodels

Timestamp:

Feb 15, 2018 11:52:38 AM (6 years ago)

Author:

Paul Kienzle <pkienzle@…>

Branches:

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

Children:

0db7dbd, 3db96b0

Parents:

547c6f0

Message:

polymer_excl_volume: note in the code that scipy gammainc is regularized, hence the gamma scale factor. Refs #1073

File:

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

sasmodels/models/polymer_excl_volume.py

@@ -151 +151 @@
     with errstate(divide='ignore', invalid='ignore'):
         upow = power(usub, -0.5*porod_exp)
+        # Note: scipy gammainc is "regularized", being gamma(s,x)/Gamma(s),
+        # so need to scale by Gamma(s) to recover gamma(s, x).
         result = (porod_exp*upow *
                   (gamma(0.5*porod_exp)*gammainc(0.5*porod_exp, usub) -