'Reinitializes the state of the algorithm.
This method should be redefined if using something other than GMState.
If only subclassing GraphMatcher, a redefinition is not necessary.'

def initialize(self):

    self.core_1 = {}
    self.core_2 = {}
    self.inout_1 = {}
    self.inout_2 = {}
    self.state = GMState(self)
    self.mapping = self.core_1.copy()
