From 5382dc1520d81eb94f670f7ee11873e6b6ffbf37 Mon Sep 17 00:00:00 2001
From: rowanc1 <rowan@visiblegeology.com>
Date: Mon, 19 May 2014 11:08:13 -0700
Subject: [PATCH] duck typing

---
 SimPEG/Optimization.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/SimPEG/Optimization.py b/SimPEG/Optimization.py
index a2d65e28..662e30da 100644
--- a/SimPEG/Optimization.py
+++ b/SimPEG/Optimization.py
@@ -669,7 +669,6 @@ class BFGS(Minimize, Remember):
 
     @bfgsH0.setter
     def bfgsH0(self, value):
-        assert type(value) is Solver, 'bfgsH0 must be a SimPEG.Solver'
         self._bfgsH0 = value
 
     def _startup_BFGS(self,x0):
@@ -687,7 +686,7 @@ class BFGS(Minimize, Remember):
     def bfgsrec(self,k,n,nn,S,Y,d):
         """BFGS recursion"""
         if k < 0:
-            d = self.bfgsH0 * d
+            d = self.bfgsH0 * d   #Assume that bfgsH0 is a SimPEG.Solver
         else:
             khat    = 0 if nn is 0 else np.mod(n-nn+k,nn)
             gamma   = np.vdot(S[:,khat],d)/np.vdot(Y[:,khat],S[:,khat])