diff --git a/GPy/core/transformations.py b/GPy/core/transformations.py
index 8982e939..ff821851 100644
--- a/GPy/core/transformations.py
+++ b/GPy/core/transformations.py
@@ -50,7 +50,9 @@ class logexp_clipped(transformation):
         ef = np.exp(f)
         gf = (ef - 1.) / ef
         return np.where(f < 1e-6, 0, gf)
-    def initialize(self, f):
+    def initialize(self,f):
+        if np.any(f<0.):
+            print "Warning: changing parameters to satisfy constraints"
         return np.abs(f)
     def __str__(self):
         return '(+ve)'
@@ -65,6 +67,8 @@ class exponent(transformation):
     def gradfactor(self, f):
         return f
     def initialize(self, f):
+        if np.any(f<0.):
+            print "Warning: changing parameters to satisfy constraints"
         return np.abs(f)
     def __str__(self):
         return '(+ve)'
@@ -79,6 +83,8 @@ class negative_exponent(transformation):
     def gradfactor(self, f):
         return f
     def initialize(self, f):
+        if np.any(f>0.):
+            print "Warning: changing parameters to satisfy constraints"
         return -np.abs(f)
     def __str__(self):
         return '(-ve)'
@@ -108,9 +114,11 @@ class logistic(transformation):
     def finv(self, f):
         return np.log(np.clip(f - self.lower, 1e-10, np.inf) / np.clip(self.upper - f, 1e-10, np.inf))
     def gradfactor(self, f):
-        return (f - self.lower) * (self.upper - f) / self.difference
-    def initialize(self, f):
-        return self.f(f * 0.)
+        return (f-self.lower)*(self.upper-f)/self.difference
+    def initialize(self,f):
+        if np.any(np.logical_or(f<self.lower,f>self.upper)):
+            print "Warning: changing parameters to satisfy constraints"
+        return np.where(np.logical_or(f<self.lower,f>self.upper),self.f(f*0.),f)
     def __str__(self):
         return '({},{})'.format(self.lower, self.upper)