Changeset 217590b in sasmodels for sasmodels/models/lib

Timestamp:

Oct 20, 2016 4:48:48 PM (8 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:

5c94f41

Parents:

2b9e63f

git-author:

Paul Kienzle <pkienzle@…> (10/20/16 16:47:25)

git-committer:

Paul Kienzle <pkienzle@…> (10/20/16 16:48:48)

Message:

fractal, fractal_core_shell: support fractal_dim as low as 0.

Location:

sasmodels/models/lib

Files:

• fractal_sq.c (added)
• sas_gamma.c (modified) (1 diff)

sasmodels/models/lib/sas_gamma.c

@@ -137 +137 @@
 
 
-inline double sas_gamma( double x) { return tgamma(x+1)/x; }
+inline double sas_gamma(double x) {
+#if 1
+    // Fast reliable gamma in [-n,171], where n is a small integer
+    double norm = 1.;
+    while (x < 1.) {
+        norm *= x;
+        x += 1.0;
+    }
+    return tgamma(x)/norm;
+#else
+    // Fast reliable gamma in [0,170]
+    return tgamma(x+1)/x;
+#endif
+}