Merge pull request #1344 from KrisThielemans/fixHessian

fix STIR.ObjectiveFunction.accumulate_Hessian_times_input

Author: KrisThielemans

src/xSTIR/pSTIR/STIR.py

@@ -2880,7 +2880,7 @@ def accumulate_Hessian_times_input(self, current_estimate, input_, subset=-1, ou
         """Computes the multiplication of the Hessian at current_estimate with a vector and adds it to output.
         """
         if out is None or out.handle is None:
-            out = input_.clone()
+            out = input_.get_uniform_copy(0.0)
         try_calling(pystir.cSTIR_objectiveFunctionAccumulateHessianTimesInput
             (self.handle, current_estimate.handle, input_.handle, subset, out.handle))
         return out
@@ -2889,7 +2889,7 @@ def multiply_with_Hessian(self, current_estimate, input_, subset=-1, out=None):
         """Computes the multiplication of the Hessian at current_estimate with a vector.
         """
         if out is None or out.handle is None:
-            out = input_.get_uniform_copy(0.0)
+            out = input_.get_uniform_copy(0.0) # actual value doesn't matter as STIR will overwrite it.
         try_calling(pystir.cSTIR_objectiveFunctionComputeHessianTimesInput
             (self.handle, current_estimate.handle, input_.handle, subset, out.handle))
         return out