diff --git a/cuburn/genome.py b/cuburn/genome.py
index 6c4d687..5411ca2 100644
--- a/cuburn/genome.py
+++ b/cuburn/genome.py
@@ -31,8 +31,8 @@ class SplEval(object):
         self.knots.T.flat[:] = knots
 
     def find_knots(self, itime):
-        idx = np.searchsorted(self.knots[0][1:-1], itime)
-        idx = min(idx, len(self.knots[0]) - 4)
+        idx = np.searchsorted(self.knots[0], itime) - 2
+        idx = max(0, min(idx, len(self.knots[0]) - 4))
 
         times = self.knots[0][idx:idx+4]
         vals = self.knots[1][idx:idx+4]
@@ -51,15 +51,33 @@ class SplEval(object):
 
         mat = self._mat
         if deriv:
-            mat *= self._deriv ** (deriv+1)
+            mat = mat * self._deriv ** (deriv)
         val = [m1, vals[1], m2, vals[2]] * mat * np.array([[t**3, t**2, t, 1]]).T
         return val[0,0]
 
+    def _plt(self, name='SplEval'):
+        import matplotlib.pyplot as plt
+        x = np.linspace(-0.05, 1.05, 500)
+        r = x[1] - x[0]
+        derivs = [(self(i+2*r)-self(i-2*r))/(4*r) for i in x]
+        plt.figure(1)
+        plt.title(name)
+        plt.plot(x,map(self,x),x,[self(i,1) for i in x],'--',x,derivs,'r.')
+        plt.show()
+
+
+
     def __str__(self):
         return '[%g:%g]' % (self(0), self(1))
     def __repr__(self):
         return '<interp [%g:%g]>' % (self(0), self(1))
 
+    @property
+    def knotlist(self):
+        if np.std(self.knots[1]) < 1e-6:
+            return self.knots[1][0]
+        return list(self.knots.T.flat)
+
     @classmethod
     def wrap(cls, obj):
         """