question: private void feedForward ( Vec input , List < Vec > activations , List < Vec > derivatives ) { Vec x = input ; for ( int i = 0 ; i < Ws . size ( ) ; i ++ ) { Matrix W_i = Ws . get ( i ) ; Vec b_i = bs . get ( i ) ; Vec a_i = activations . get ( i ) ; a_i . zeroOut ( ) ; W_i . multiply ( x , 1 , a_i ) ; a_i . mutableAdd ( b_i ) ; a_i . applyFunction ( f ) ; Vec d_i = derivatives . get ( i ) ; a_i . copyTo ( d_i ) ; d_i . applyFunction ( f . getD ( ) ) ; x = a_i ; } }
target:  Feeds a vector through the network to get an output 