我正在用keras构建DNN，以在背景事件或信号事件（HEP）之间进行分类。不过，损失和准确性并没有改变。
我已经尝试过更改优化器上的参数，对数据进行规范化，更改层数，神经元，历元，初始化权重等。
这是模型：
epochs = 20
num_features = 2
num_classes = 2
batch_size = 32
# model
print("\n Building model...")
model = Sequential()
model.add(Dropout(0.2))
model.add(Dense(128, input_shape=(2,), activation='relu'))
model.add(Dense(128, activation='relu'))
model.add(Dense(num_classes,activation=tf.nn.softmax))
print("\n Compiling model...")
opt = adam(lr=0.0001, beta_1=0.9, beta_2=0.999, epsilon=None, decay=0.0,
amsgrad=False)
# compile model
model.compile(
loss='sparse_categorical_crossentropy',
optimizer=opt,
metrics=['accuracy'])
print("\n Fitting model...")
history = model.fit(x_train, y_train, epochs = epochs,
batch_size = batch_size, validation_data = (x_test, y_test))
我期望损失有所变化，但不会从0.69欧元下降。
时代报告
Building model...
Compiling model...
Fitting model...
Train on 18400 samples, validate on 4600 samples
Epoch 1/20
18400/18400 [==============================] - 1s 71us/step - loss: 0.6939 - acc: 0.4965 - val_loss: 0.6933 - val_acc: 0.5000
Epoch 2/20
18400/18400 [==============================] - 1s 60us/step - loss: 0.6935 - acc: 0.5045 - val_loss: 0.6933 - val_acc: 0.5000
Epoch 3/20
18400/18400 [==============================] - 1s 69us/step - loss: 0.6937 - acc: 0.4993 - val_loss: 0.6934 - val_acc: 0.5000
Epoch 4/20
18400/18400 [==============================] - 1s 65us/step - loss: 0.6939 - acc: 0.4984 - val_loss: 0.6932 - val_acc: 0.5000
Epoch 5/20
18400/18400 [==============================] - 1s 58us/step - loss: 0.6936 - acc: 0.5000 - val_loss: 0.6936 - val_acc: 0.5000
Epoch 6/20
18400/18400 [==============================] - 1s 57us/step - loss: 0.6937 - acc: 0.4913 - val_loss: 0.6932 - val_acc: 0.5000
Epoch 7/20
18400/18400 [==============================] - 1s 58us/step - loss: 0.6935 - acc: 0.5008 - val_loss: 0.6932 - val_acc: 0.5000
Epoch 8/20
18400/18400 [==============================] - 1s 63us/step - loss: 0.6936 - acc: 0.5013 - val_loss: 0.6936 - val_acc: 0.5000
Epoch 9/20
18400/18400 [==============================] - 1s 67us/step - loss: 0.6936 - acc: 0.4924 - val_loss: 0.6932 - val_acc: 0.5000
Epoch 10/20
18400/18400 [==============================] - 1s 61us/step - loss: 0.6933 - acc: 0.5067 - val_loss: 0.6934 - val_acc: 0.5000
Epoch 11/20
18400/18400 [==============================] - 1s 64us/step - loss: 0.6938 - acc: 0.4972 - val_loss: 0.6931 - val_acc: 0.5000
Epoch 12/20
18400/18400 [==============================] - 1s 64us/step - loss: 0.6936 - acc: 0.4991 - val_loss: 0.6934 - val_acc: 0.5000
Epoch 13/20
18400/18400 [==============================] - 1s 70us/step - loss: 0.6937 - acc: 0.4960 - val_loss: 0.6935 - val_acc: 0.5000
Epoch 14/20
18400/18400 [==============================] - 1s 63us/step - loss: 0.6935 - acc: 0.4992 - val_loss: 0.6932 - val_acc: 0.5000
Epoch 15/20
18400/18400 [==============================] - 1s 61us/step - loss: 0.6937 - acc: 0.4940 - val_loss: 0.6931 - val_acc: 0.5000
Epoch 16/20
18400/18400 [==============================] - 1s 68us/step - loss: 0.6933 - acc: 0.5067 - val_loss: 0.6936 - val_acc: 0.5000
Epoch 17/20
18400/18400 [==============================] - 1s 58us/step - loss: 0.6938 - acc: 0.4997 - val_loss: 0.6935 - val_acc: 0.5000
Epoch 18/20
18400/18400 [==============================] - 1s 56us/step - loss: 0.6936 - acc: 0.4972 - val_loss: 0.6941 - val_acc: 0.5000
Epoch 19/20
18400/18400 [==============================] - 1s 57us/step - loss: 0.6934 - acc: 0.5061 - val_loss: 0.6954 - val_acc: 0.5000
Epoch 20/20
18400/18400 [==============================] - 1s 58us/step - loss: 0.6936 - acc: 0.5037 - val_loss: 0.6939 - val_acc: 0.5000
更新：我的数据准备中包含了
np.random.shuffle(x_train)
np.random.shuffle(y_train)
np.random.shuffle(x_test)
np.random.shuffle(y_test)
而且我认为它正在更改每个数据点的类，因为改组是分别完成的。