Changeset 6d96b66 in sasmodels for sasmodels/models/mass_surface_fractal.c

Timestamp:

Oct 18, 2016 10:32:18 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:

f0afad2

Parents:

3e8ea5d

Message:

fractal models: handle limits of q=0 and dim=1

File:

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

sasmodels/models/mass_surface_fractal.c

@@ -1 @@
-double form_volume(double radius);
-
-double Iq(double q,
-          double fractal_dim_mass,
-          double fractal_dim_surf,
-          double rg_cluster,
-          double rg_primary);
-
-static double _mass_surface_fractal_kernel(double q,
+#define INVALID(p) (p.fractal_dim_mass + p.fractal_dim_surf > 6.)
+static double
+Iq(double q,
           double fractal_dim_mass,
           double fractal_dim_surf,
@@ -14 +8 @@
 {
      //computation
-    double tot_dim = 6.0 - fractal_dim_surf - fractal_dim_mass;
-    fractal_dim_mass /= 2.0;
-    tot_dim /= 2.0;
+    const double Dm = 0.5*fractal_dim_mass;
+    const double Dt = 0.5*(6.0 - (fractal_dim_mass + fractal_dim_surf));
 
-    double rc_norm = rg_cluster * rg_cluster / (3.0 * fractal_dim_mass);
-    double rp_norm = rg_primary * rg_primary / (3.0 * tot_dim);
+    const double t1 = Dm==0. ? 1.0 : pow(1.0 + square(q*rg_cluster)/(3.0*Dm), -Dm);
+    const double t2 = Dt==0. ? 1.0 : pow(1.0 + square(q*rg_primary)/(3.0*Dt), -Dt);
+    const double form = t1*t2;
 
-    //x for P
-    double x_val1 = 1.0 +  q * q * rc_norm;
-    double x_val2 = 1.0 +  q * q * rp_norm;
-
-    double inv_form = pow(x_val1, fractal_dim_mass) * pow(x_val2, tot_dim);
-
-    //another singular
-    if (inv_form == 0.0) return 0.0;
-
-    double form_factor = 1.0;
-    form_factor /= inv_form;
-
-    return (form_factor);
+    return form;
 }
-double form_volume(double radius){
-
-    return M_4PI_3*radius*radius*radius;
-}
-
-double Iq(double q,
-          double fractal_dim_mass,
-          double fractal_dim_surf,
-          double rg_cluster,
-          double rg_primary)
-{
-    return _mass_surface_fractal_kernel(q,
-            fractal_dim_mass,
-            fractal_dim_surf,
-            rg_cluster,
-            rg_primary);
-}