Index: trunk/Ohana/src/opihi/cmd.data/vgauss.c
===================================================================
--- trunk/Ohana/src/opihi/cmd.data/vgauss.c	(revision 41340)
+++ trunk/Ohana/src/opihi/cmd.data/vgauss.c	(revision 41341)
@@ -3,4 +3,5 @@
 /* local private functions */
 opihi_flt fgaussOD (opihi_flt, opihi_flt *, int, opihi_flt *);
+int vgauss_apply (int argc, char **argv);
 
 # define GET_VAR(V,A) \
@@ -20,4 +21,10 @@
   Vector *xvec, *yvec, *svec, *ovec;
   char *c, name[16];
+
+  if ((N = get_argument (argc, argv, "-apply"))) {
+    remove_argument (N, &argc, argv);
+    int status = vgauss_apply (argc, argv);
+    return status;
+  }
 
   Quiet = FALSE;
@@ -104,4 +111,6 @@
   }  
   if (!Quiet) gprint (GP_ERR, "%d iterations\n", i); 
+  set_variable ("Chisq", chisq);
+  set_variable ("ChisqNu", chisq / (float) (Npts - Npar));
 
   for (i = 0; i < Npts; i++) {
@@ -125,4 +134,38 @@
 }
 
+int vgauss_apply (int argc, char **argv) {
+
+  opihi_flt par[4];
+  Vector *xvec, *ovec;
+  char *c;
+
+  // NOTE: -apply has already been stripped by vgauss call
+  if (argc != 3) {
+    gprint (GP_ERR, "USAGE: vgauss -apply <x> <out>\n");
+    return (FALSE);
+  }
+  
+  if ((xvec = SelectVector (argv[1], OLDVECTOR, TRUE)) == NULL) return (FALSE);
+  if ((ovec = SelectVector (argv[2], ANYVECTOR, TRUE)) == NULL) return (FALSE);
+
+  CastVector (xvec, OPIHI_FLT);
+
+  GET_VAR (par[0], "C0");
+  GET_VAR (par[1], "C1");
+  GET_VAR (par[2], "C2");
+  GET_VAR (par[3], "C3");
+  int Npar = 4;
+
+  int Npts = xvec[0].Nelements;
+  ResetVector (ovec, OPIHI_FLT, Npts);
+
+  for (int i = 0; i < Npts; i++) {
+    ovec[0].elements.Flt[i] = fgaussOD (xvec[0].elements.Flt[i], par, Npar, NULL);
+  }
+  ovec[0].Nelements = Npts;
+
+  return TRUE;
+}
+
 /* pars: x_o, sigma, I, back */
 opihi_flt fgaussOD (opihi_flt x, opihi_flt *par, int Npar, opihi_flt *dpar) {
@@ -135,8 +178,10 @@
   f = par[2]*r + par[3];
 
-  dpar[0] = par[2]*r*z/par[1];
-  dpar[1] = par[2]*r*z*z/par[1];
-  dpar[2] = r;
-  dpar[3] = 1;
+  if (dpar) {
+    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);