'Initialize negative particles.
Copies the pos state and samples it to initialize the ngative particles.'

def InitializeNegPhase(self, to_pos=False):

    for layer in self.layer:
        self.SetPhase(layer, pos=False)
        if to_pos:
            layer.state.assign(layer.pos_state)
        else:
            layer.ResetState(rand=True)
        layer.Sample()
        self.SetPhase(layer, pos=True)
