def col_softmax(x):
x = np.asarray(x)
x_col_max = x.max(axis=0)
x_col_max = x_col_max.reshape([1,x.shape[1]])
x = x - x_col_max # 防止数值上溢
x_exp = np.exp(x)
x_exp_col_sum = x_exp.sum(axis=0).reshape([1,x.shape[1]])
softmax = x_exp / x_exp_col_sum
return softmax
测试
a = [[i] for i in range(20)]
col_softmax(a)
'''
array([[3.54164282e-09],
[9.62718333e-09],
[2.61693975e-08],
[7.11357977e-08],
[1.93367146e-07],
[5.25626400e-07],
[1.42880069e-06],
[3.88388295e-06],
[1.05574885e-05],
[2.86982290e-05],
[7.80098745e-05],
[2.12052824e-04],
[5.76419339e-04],
[1.56687021e-03],
[4.25919483e-03],
[1.15776919e-02],
[3.14714295e-02],
[8.55482150e-02],
[2.32544158e-01],
[6.32120560e-01]])
'''