Index: trunk/psphot/src/models/pmModel_RGAUSS.c
===================================================================
--- trunk/psphot/src/models/pmModel_RGAUSS.c	(revision 8882)
+++ trunk/psphot/src/models/pmModel_RGAUSS.c	(revision 9529)
@@ -30,9 +30,9 @@
     psF32 p  = pow(z, PAR[PM_PAR_7] - 1.0);
     psF32 r  = 1.0 / (1 + z + z*p);
-    psF32 f  = PAR[PM_PAR_FLUX]*r + PAR[PM_PAR_SKY];
+    psF32 f  = PAR[PM_PAR_I0]*r + PAR[PM_PAR_SKY];
 
     if (deriv != NULL) {
         // note difference from a pure gaussian: q = params->data.F32[1]*r
-        psF32 t = PAR[PM_PAR_FLUX]*r*r;
+        psF32 t = PAR[PM_PAR_I0]*r*r;
 	psF32 q = t*(1 + PAR[PM_PAR_7]*p);
 
@@ -87,11 +87,11 @@
 
     if (flux <= 0) return (1.0);
-    if (PAR[PM_PAR_FLUX] <= 0) return (1.0);
-    if (flux >= PAR[PM_PAR_FLUX]) return (1.0);
+    if (PAR[PM_PAR_I0] <= 0) return (1.0);
+    if (flux >= PAR[PM_PAR_I0]) return (1.0);
 
     // if Sx == Sy, sigma = Sx == Sy
     psF64 sigma = hypot (1.0 / PAR[PM_PAR_SXX], 1.0 / PAR[PM_PAR_SYY]) / sqrt(2.0);
     psF64 dz = 1.0 / (2.0 * sigma*sigma);
-    psF64 limit = flux / PAR[PM_PAR_FLUX];
+    psF64 limit = flux / PAR[PM_PAR_I0];
 
     // we can do this much better with intelligent choices here