if (forBackprop && !sigmoidGates) {
                    if(shouldCache(training, cacheMode, workspaceMgr)){
                        cacheEnter(training, cacheMode, workspaceMgr);
                        toReturn.fz[time] = forgetGateActivations.dup('f'); //Forget gate pre-out (z)
                        cacheExit(training, cacheMode, workspaceMgr);