So far it has been assumed that the net is started in some initial state (the memory cue) and the whole net allowed to run freely until a state cycle is encountered (recall slide of noisy `T'). There is another possibility in which some part of the net has its outputs fixed while the remainder is allowed to update. The part that is fixed is said to be clamped and if the clamp forms part of a state cycle, the remainder (unclamped) part of the net will complete the pattern stored at that cycle (recall slide of partially correct `T'). Which mode is used will depend on any prior knowledge about parts of the cue being uncorrupted or noise free.
The problem of how to fix the weights in Hopfield nets will be dealt with next time.