diff --git a/mclmc/dynamics.py b/mclmc/dynamics.py
index dab1f84..4b00f61 100644
--- a/mclmc/dynamics.py
+++ b/mclmc/dynamics.py
@@ -86,10 +86,10 @@ def step(x, u, g, eps, sigma):
       # V T V T V
       uu, r1 = V(eps * lambda_c, u, g * sigma)
       xx, ll, gg, reflect = T(eps, x, 0.5*uu*sigma)
-      uu = (1 - 2 * reflect) * uu
+      uu *= reflect
       uu, r2 = V(eps * (1 - 2 * lambda_c), uu, gg * sigma)
       xx, ll, gg, reflect = T(eps, xx, 0.5*uu*sigma)
-      uu = (1 - 2 * reflect) * uu
+      uu *= reflect
       uu, r3 = V(eps * lambda_c, uu, gg * sigma)
 
       #kinetic energy change
@@ -108,9 +108,9 @@ def step(x, u, g, eps, sigma):
     # V T V
     uu, r1 = V(eps * 0.5, u, g * sigma)
     xx, l, gg, reflect = T(eps, x, uu*sigma)
-    uu = (1 - 2 * reflect) * uu
+    uu *= reflect
     uu, r2 = V(eps * 0.5, uu, gg * sigma)
-    
+
     # kinetic energy change
     kinetic_change = (r1 + r2) * (d-1)
 
diff --git a/mclmc/sampler.py b/mclmc/sampler.py
index a73fb7b..eb4edc8 100644
--- a/mclmc/sampler.py
+++ b/mclmc/sampler.py
@@ -307,9 +307,11 @@ def single_chain_sample(self, num_steps, x_initial, random_key, output, thinning
 
         ### sampling ###
 
+        hyp = Parameters(L, eps, sigma)
+        self.hyp = hyp
         
         if output == OutputType.normal or output == OutputType.detailed:
-            X, _, E = self.sample_normal(num_steps, MCLMCState(x, u, l, g, key), Parameters(L, eps, sigma), thinning)
+            X, _, E = self.sample_normal(num_steps, MCLMCState(x, u, l, g, key), hyp, thinning)
             if output == OutputType.detailed:
                 return X, E, L, eps
             else:
@@ -537,8 +539,11 @@ def positive(self, where):
         """
         mask = self.to_mask(where)
         
-        self.map = lambda x: (jnp.abs(x) * mask + x * (1- mask), x < 0.)
+        self.map = lambda x: (jnp.abs(x) * mask + x * (1- mask), self.to_reflect((x < 0.) * mask))
 
+    def to_reflect(self, mask):
+        return 1 - 2 * mask
+    
 
     def rectangular(self, where, a, b):
         """Used if some parameters are rectangularly constrained (a< x < b)