Changes in / [17bbadd:754e27b] in sasmodels

Location:

sasmodels/models

Files:

• hardsphere.py (modified) (1 diff)
• stickyhardsphere.py (modified) (3 diffs)

sasmodels/models/hardsphere.py

@@ -35 +35 @@
 from numpy import inf
 
-name = "hardsphere_fish"
-title = "Hard sphere structure factor from FISH, with Percus-Yevick closure"
+name = "hardsphere"
+title = "Hard sphere structure factor, with Percus-Yevick closure"
 description = """\
     [Hard sphere structure factor, with Percus-Yevick closure]

sasmodels/models/stickyhardsphere.py

@@ -122 +122 @@
     //C  SOLVE QUADRATIC FOR LAMBDA
     //C
-    qa = eta/12.0;
-    qb = -1.0*(stickiness + eta/etam1);
+    qa = eta/6.0;
+    qb = stickiness + eta/etam1;
     qc = (1.0 + eta/2.0)/etam1sq;
-    radic = qb*qb - 4.0*qa*qc;
+    radic = qb*qb - 2.0*qa*qc;
     if(radic<0) {
         //if(x>0.01 && x<0.015)
@@ -133 +133 @@
     }
     //C   KEEP THE SMALLER ROOT, THE LARGER ONE IS UNPHYSICAL
-    lam = (-1.0*qb-sqrt(radic))/(2.0*qa);
-    lam2 = (-1.0*qb+sqrt(radic))/(2.0*qa);
+    radic = sqrt(radic);
+    lam = (qb-radic)/qa;
+    lam2 = (qb+radic)/qa;
     if(lam2<lam) {
         lam = lam2;
@@ -186 +187 @@
 tests = [
         [ {'scale': 1.0, 'background' : 0.0, 'effect_radius' : 50.0, 'perturb' : 0.05, 'stickiness' : 0.2, 'volfraction' : 0.1,
-           'effect_radius_pd' : 0}, [0.001], [1.09718]]
+           'effect_radius_pd' : 0}, [0.001, 0.003], [1.09718, 1.087830]]
         ]