<unk>  is a generalization of the recirculation algorithm, and approximates Almeida-Pineda recurrent backpropagation. It is used as part of the Leabra algorithm for error-driven learning. The symmetric, midpoint version of<unk>  is equivalent to the contrastive Hebbian learning algorithm (CHL).
GeneRec
Seegene
MChip
Clone 
DirectHit
ESKAPE
FinnGen
GeneCards