Defined in File operator_node.h
This struct is a nested type of Class OperatorNodeProp.
operator attributs that can be directly modified
topo sort priority: smaller number means higher priority
if this operator is copied from another opr or generated by graph transformation from another opr, then src_opr would be the corresponding source operator
objects associated with this opr; their memory should be managed by some UserData class attached to the computing graph
source operator that creates this opr as its gradient