Officials in Portland, Oregon, are preparing for violence to break out during a rally and an opposing event planned for Sunday. Two groups, one composed of people who describe themselves as patriots, the other made up largely of members of the so-called anti-fascist Antifa network, are planning to descend on a waterfront park on the anniversary of a huge brawl between some of the same individuals. The groups plan to confront each other, Portland police officials say. Officials are advising people to stay away from the city if they plan to instigate fights, but have also said that officers won’t prevent the looming clash. “This is our main message: if you are planning to come down to instigate fights with those you disagree with, don’t come,” Portland Police Chief Chuck Lovell said in a statement. “You should not expect to see police officers standing in the middle of the crowd …