small perf, helps with CamDavidsonPilon#271

rosejn · Dec 31, 2016 · 79f01fc · 79f01fc
1 parent 84057da
commit 79f01fc
Showing 1 changed file with 1 addition and 5 deletions.
diff --git a/lifelines/fitters/coxph_fitter.py b/lifelines/fitters/coxph_fitter.py
@@ -89,7 +89,7 @@ def _get_efron_values(self, X, beta, T, E, include_likelihood=False):
             # Calculate phi values
             phi_i = exp(dot(xi, beta))
             phi_x_i = dot(phi_i, xi)
-            phi_x_x_i = dot(xi.T, xi) * phi_i
+            phi_x_x_i = dot(xi.T, phi_i * xi)
 
             # Calculate sums of Risk set
             risk_phi += phi_i
@@ -121,10 +121,6 @@ def _get_efron_values(self, X, beta, T, E, include_likelihood=False):
                 denom = (risk_phi - c * tie_phi)
                 z = (risk_phi_x - c * tie_phi_x)
 
-                if denom == 0:
-                    # Can't divide by zero
-                    raise ValueError("Denominator was zero")
-
                 # Gradient
                 partial_gradient += z / denom
                 # Hessian