Changeset 1ec7efa in sasmodels

Timestamp:

Nov 25, 2015 4:44:45 PM (9 years ago)

Author:

Paul Kienzle <pkienzle@…>

Branches:

master, core_shell_microgels, costrafo411, magnetic_model, release_v0.94, release_v0.95, ticket-1257-vesicle-product, ticket_1156, ticket_1265_superball, ticket_822_more_unit_tests

Children:

d138d43

Parents:

a5899c8

Message:

use taylor expansion in triaxial ellipsoid model so single precision is more accurate

Location:

sasmodels

Files:

• compare.py (modified) (1 diff)
• models/triaxial_ellipsoid.c (modified) (1 diff)

sasmodels/compare.py

@@ -292 +292 @@
         except ImportError:
             traceback.print_exc()
-            Ncomp = 0
+            Nbase = 0
     elif Nbase > 0:
         base, base_time = eval_opencl(model_definition, pars, data,

sasmodels/models/triaxial_ellipsoid.c

@@ -37 +37 @@
             const double t = q*sqrt(acosx2 + bsinx2*(1.0-y*y) + c2*y*y);
             SINCOS(t, st, ct);
-            const double fq = ( t==0.0 ? 1.0 : 3.0*(st-t*ct)/(t*t*t) );
+            //const double fq = ( t==0.0 ? 1.0 : 3.0*(st-t*ct)/(t*t*t) );
+            const double tsq = t*t;
+            const double fq = (t < 1e-1)
+                ? 1.0 + tsq*(-3./30. + tsq*(3./840. + tsq*(-3./45360.)))// + tsq*(3./3991680.))))
+                : 3.0*(st/t - ct)/tsq;
             inner += Gauss76Wt[j] * fq * fq ;
         }