delta_w = L_hbias.transpose().mmul(my_samples).addi(y.transpose().mmul(L_vbias));
}
if (myConfig.isUseRegularization()) {
//only L2 for autoencoder
if (0 != myConfig.getLamada2()) {
delta_w.subi(my_w.mul(myConfig.getLamada2()));
}
}
delta_w.divi(nbr_sample);
DoubleMatrix delta_hbias = L_hbias.columnSums().divi(nbr_sample);
DoubleMatrix delta_vbias = L_vbias.columnSums().divi(nbr_sample);