optim.py 文件源码

def AdaMaxAvg2(ws, objective, alpha=.01, beta1=.1, beta2=.001, beta3=0.01, n_accum=1):
    if n_accum == 1:
        return AdaMaxAvg(ws, objective, alpha, beta1, beta2, beta3)
    print 'AdaMax_Avg2', 'alpha:',alpha,'beta1:',beta1,'beta2:',beta2,'beta3:',beta3,'n_accum:',n_accum

    gs = G.ndict.T_grad(objective.sum(), ws, disconnected_inputs='raise')

    new = OrderedDict()

    from theano.ifelse import ifelse
    it = G.sharedf(0.)
    new[it] = it + 1
    reset = T.eq(T.mod(it,n_accum), 0)
    update = T.eq(T.mod(it,n_accum), n_accum-1)

    ws_avg = []
    for j in range(len(ws)):
        w_avg = {}
        for i in ws[j]:
            _w = ws[j][i]
            _g = gs[j][i]
            #_g = T.switch(T.isnan(_g),T.zeros_like(_g),_g) #remove NaN's
            mom1 = G.sharedf(_w.get_value() * 0.)
            _max = G.sharedf(_w.get_value() * 0.)
            w_avg[i] = G.sharedf(_w.get_value())
            g_sum = G.sharedf(_w.get_value() * 0.)

            new[g_sum] = ifelse(reset, _g, g_sum + _g)
            new[mom1] = ifelse(update, (1-beta1) * mom1 + beta1 * new[g_sum], mom1)
            new[_max] = ifelse(update, T.maximum((1-beta2)*_max, abs(new[g_sum]) + 1e-8), _max)
            new[_w] = ifelse(update, _w + alpha *  new[mom1] / new[_max], _w)
            new[w_avg[i]] = ifelse(update, beta3 * new[_w] + (1.-beta3) * w_avg[i], w_avg[i])
        ws_avg += [w_avg]   
    return new, ws_avg