Changeset 10071

Timestamp:

Nov 17, 2006, 5:03:10 PM (20 years ago)

Author:

eugene

Message:

fixed up sigma representation

File:

• trunk/Ohana/src/opihi/cmd.data/vgauss.c (modified) (3 diffs)

trunk/Ohana/src/opihi/cmd.data/vgauss.c

@@ -49 +49 @@
   GET_VAR (par[2], "C2");
   GET_VAR (par[3], "C3");
-  par[1] = sqrt(0.5)*(1/par[1]);
   Npar = 4;
-  /* careful of variable renomalization */
 
   v1 = svec[0].elements;
@@ -75 +73 @@
 
   covar = mrqcovar (Npar);
-  par[1] = sqrt(0.5)*(1/par[1]);
   for (i = 0; i < Npar; i++) {
     sprintf (name, "C%d", i);
@@ -88 +85 @@
 }
 
-/* pars: x_o, -0.5/sigma^2, I, back*/
+/* pars: x_o, sigma, I, back */
 float fgaussOD (float x, float *par, int Npar, float *dpar) {
 
-  float z, r, f, q;
+  float z, r, f;
 
-  z = (x - par[0]);
-  r = exp (-1*SQ(par[1]*z));
+  z = (x - par[0])/par[1];
+  r = exp (-0.5*SQ(z));
   f = par[2]*r + par[3];
-  q = 2*par[1]*par[2]*r*z;
 
-  dpar[0] = +q*par[1];
-  dpar[1] = -q*z;
+  dpar[0] = par[2]*r*z/par[1];
+  dpar[1] = par[2]*r*z*z/par[1];
   dpar[2] = r;
   dpar[3] = 1;
   
   return (f);
-
 }