Changeset 483 for trunk

Timestamp:

10/06/2009 06:27:25 PM (3 years ago)

Author:

powell

Message:

Binary iteration preceding secant iteration for better edge effectiveness.

Files:

• trunk/matml/src/ternary/spinodal.c (modified) (3 diffs)

trunk/matml/src/ternary/spinodal.c

@@ -12 +12 @@
 
 /*++++++++++++++++++++++++++++++++++++++
-  This function uses secant iteration to estimate the root of the spinodal
-  function on a line in ternary space between points A and B.
+  This function uses dissection and secant iteration to estimate the root of
+  the spinodal function on a line in ternary space between points A and B.
 
   inline double interpolate Returns the fraction B whose weighted average with
@@ -46 +46 @@
  double T, double P, energy_params *eparams, int efunc, int iters)
 {
-  int i;
+  int i, binaries=10;
   energy_point X;
   double interp=0., intfrac=1., XS;
+
+  for (i=0; i<binaries; i++)
+    {
+      X.C2 = 0.5 * (A2+B2);
+      X.C3 = 0.5 * (A3+B3);
+      X.efunc = -1;
+      free_energies (&X, 1, T,P, eparams,efunc, WITH_DERIVATIVES_NO_INFINITY);
+      XS = X.G22 * X.G33 - X.G23 * X.G23;
+
+      if (AS * XS > 0)
+        {
+          interp += intfrac * 0.5;
+          intfrac *= 0.5;
+          A2 = X.C2;
+          A3 = X.C3;
+          AS = XS;
+        }
+      else
+        {
+          intfrac *= 0.5;
+          B2 = X.C2;
+          B3 = X.C3;
+          BS = XS;
+        }
+    }
 
   for (i=0; i<iters; i++)
@@ -54 +79 @@
       X.C2 = (AS*B2 - BS*A2) / (AS - BS);
       X.C3 = (AS*B3 - BS*A3) / (AS - BS);
-
       X.efunc = -1;
       free_energies (&X, 1, T,P, eparams,efunc, WITH_DERIVATIVES_NO_INFINITY);
       XS = X.G22 * X.G33 - X.G23 * X.G23;
-
-      printf ("A=%g,%g->%g B=%g,%g->%g, X=%g,%g->%g\n", A2,A3,AS, B2,B3,BS,
-              X.C2,X.C3,XS);
 
       if (AS * XS > 0)