Index: trunk/psModules/src/objects/models/pmModel_GAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_GAUSS.c	(revision 14208)
+++ trunk/psModules/src/objects/models/pmModel_GAUSS.c	(revision 14220)
@@ -71,5 +71,7 @@
         f2 = 1.0 / PS_SQR(params[PM_PAR_SYY]) - 1.0 / PS_SQR(params[PM_PAR_SXX]);
         q1 = PS_SQR(f1)*AR_RATIO - PS_SQR(f2);
-        assert (q1 > 0);
+	q1 = PS_MAX (0.0, q1); 
+	// if q1 < 0.0, f2 ~ f1, we have a very large axis ratio near 45deg..  Saturate at that
+	// angle and let f2,f1 fight it out
         q2  = 0.5*sqrt (q1);
     }
@@ -97,5 +99,5 @@
             break;
         case PM_PAR_SXY:
-            beta_lim =  q2;
+            beta_lim =  0.5*q2;
             break;
         default:
Index: trunk/psModules/src/objects/models/pmModel_PGAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_PGAUSS.c	(revision 14208)
+++ trunk/psModules/src/objects/models/pmModel_PGAUSS.c	(revision 14220)
@@ -39,4 +39,6 @@
     psF32 py = Y / PAR[PM_PAR_SYY];
     psF32 z  = PS_SQR(px) + PS_SQR(py) + PAR[PM_PAR_SXY]*X*Y;
+    assert (z >= 0.0);
+
     psF32 t  = 1 + z + z*z/2.0;
     psF32 r  = 1.0 / (t + z*z*z/6.0); /* exp (-Z) */
@@ -63,4 +65,13 @@
 # define AR_MAX 20.0
 # define AR_RATIO 0.99
+
+// we constraint limits by the min valid minor axis:
+# define MIN_MINOR_AXIS 0.5
+
+// f3 = (s_b^-2 - s_a^-2); F3_SQ_MAX is MIN_MINOR_AXIS^-4
+# define F3_SQ_MAX 16.0 
+
+static float saveParams[8];
+
 bool PM_MODEL_LIMITS (psMinConstraintMode mode, int nParam, float *params, float *beta)
 {
@@ -73,5 +84,7 @@
         f2 = 1.0 / PS_SQR(params[PM_PAR_SYY]) - 1.0 / PS_SQR(params[PM_PAR_SXX]);
         q1 = PS_SQR(f1)*AR_RATIO - PS_SQR(f2);
-        assert (q1 > 0);
+	q1 = PS_MAX (0.0, q1); 
+	// if q1 < 0.0, f2 ~ f1, we have a very large axis ratio near 45deg..  Saturate at that
+	// angle and let f2,f1 fight it out
         q2  = 0.5*sqrt (q1);
     }
@@ -93,11 +106,11 @@
             break;
         case PM_PAR_SXX:
-            beta_lim = 0.5;
+            beta_lim = 2.0;
             break;
         case PM_PAR_SYY:
-            beta_lim = 0.5;
+            beta_lim = 2.0;
             break;
         case PM_PAR_SXY:
-            beta_lim =  q2;
+            beta_lim =  0.5*q2;
             break;
         default:
@@ -137,5 +150,6 @@
             psAbort("invalid parameter %d for param min test", nParam);
         }
-        if (params[nParam] < params_min) {
+	saveParams[nParam] = params[nParam];
+	if (params[nParam] < params_min) {
             params[nParam] = params_min;
 	    psTrace ("psModules.objects", 5, "params[nParam==%d] < params_min; %g v. %g",
@@ -170,4 +184,5 @@
             psAbort("invalid parameter %d for param max test", nParam);
         }
+	saveParams[nParam] = params[nParam];
         if (params[nParam] > params_max) {
             params[nParam] = params_max;
Index: trunk/psModules/src/objects/models/pmModel_QGAUSS.c
===================================================================
--- trunk/psModules/src/objects/models/pmModel_QGAUSS.c	(revision 14208)
+++ trunk/psModules/src/objects/models/pmModel_QGAUSS.c	(revision 14220)
@@ -88,8 +88,7 @@
         f2 = 1.0 / PS_SQR(params[PM_PAR_SYY]) - 1.0 / PS_SQR(params[PM_PAR_SXX]);
         q1 = PS_SQR(f1)*AR_RATIO - PS_SQR(f2);
-        if (q1 <= 0) {
-	    psError(PM_ERR_PSF, true, "Q1 < 0 (%g)", q1);
-	    return false;
-	}
+	q1 = (q1 < 0.0) ? 0.0 : q1;
+	// if q1 < 0.0, f2 ~ f1, we have a very large axis ratio near 45deg..  Saturate at that
+	// angle and let f2,f1 fight it out
         q2  = 0.5*sqrt (q1);
     }
@@ -117,5 +116,5 @@
             break;
         case PM_PAR_SXY:
-            beta_lim =  q2;
+            beta_lim =  0.5*q2;
             break;
         case PM_PAR_7: