Norm2sq does not fail if cannot calculate Lipschitz constant

1 files changed, 9 insertions, 5 deletions

diff --git a/Wrappers/Python/ccpi/optimisation/funcs.py b/Wrappers/Python/ccpi/optimisation/funcs.py
index 2266560..c7a6143 100755
--- a/Wrappers/Python/ccpi/optimisation/funcs.py
+++ b/Wrappers/Python/ccpi/optimisation/funcs.py
@@ -136,6 +136,8 @@ class Norm2sq(Function):
     '''
     
     def __init__(self,A,b,c=1.0,memopt=False):
+        super(Norm2sq, self).__init__()
+    
         self.A = A  # Should be an operator, default identity
         self.b = b  # Default zero DataSet?
         self.c = c  # Default 1.
@@ -146,11 +148,13 @@ class Norm2sq(Function):
             self.adjoint_placehold = A.allocate_adjoint()
             
         
-        # Compute the Lipschitz parameter from the operator.
-        # Initialise to None instead and only call when needed.
-        self.L = 2.0*self.c*(self.A.get_max_sing_val()**2)
-        super(Norm2sq, self).__init__()
-    
+        # Compute the Lipschitz parameter from the operator if possible
+        # Leave it initialised to None otherwise
+        try:
+            self.L = 2.0*self.c*(self.A.get_max_sing_val()**2)
+        except AttributeError as ae:
+            pass
+        
     def grad(self,x):
         #return 2*self.c*self.A.adjoint( self.A.direct(x) - self.b )
         return (2.0*self.c)*self.A.adjoint( self.A.direct(x) - self.b )