Changeset 98ce141 in sasmodels for sasmodels/models/stacked_disks.c

Timestamp:

Nov 27, 2016 4:25:24 PM (7 years ago)

Author:

butler

Branches:

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

Children:

07300ea

Parents:

797a8e3

Message:

correct normalization problem in stacked_disk fixes #789. Also heavy
cleanup and correction of equations to match code as well as
standardization of the model documentation addressing #646.

File:

• sasmodels/models/stacked_disks.c (modified) (2 diffs)

sasmodels/models/stacked_disks.c

@@ -71 +71 @@
     // loop for the structure factor S(q)
     double qd_cos_alpha = q*d*cos_alpha;
+    //d*cos_alpha is the projection of d onto q (in other words the component
+    //of d that is parallel to q.
     double debye_arg = -0.5*square(qd_cos_alpha*sigma_dnn);
     double sq=0.0;
@@ -79 +81 @@
     sq = 1.0 + 2.0*sq/n_stacking;
 
-    return pq * sq;
+    return pq * sq * n_stacking;
+    // volume normalization should be per disk not per stack but form_volume
+    // is per stack so correct here for now.  Could change form_volume but
+    // if one ever wants to use P*S we need the ER based on the total volume
 }