Logits and labels must have same shape for Keras model

Question

I am new to Keras and have been practicing with resources from the web. Unfortunately, I cannot build a model without it throwing the following error:

ValueError: logits and labels must have the same shape, received ((None, 10) vs (None, 1)).

I have attempted the following:

DF = pd.read_csv("https://raw.githubusercontent.com/EpistasisLab/tpot/master/tutorials/MAGIC%20Gamma%20Telescope/MAGIC%20Gamma%20Telescope%20Data.csv")

X = DF.iloc[:,0:-1]
y = DF.iloc[:,-1]
yBin = np.array([1 if x == 'g' else 0 for x in y ])
scaler = StandardScaler()
X1 = scaler.fit_transform(X)
X_train, X_test, y_train, y_test = train_test_split(X1, yBin, test_size=0.25, random_state=2018) 

print(X_train.__class__,X_test.__class__,y_train.__class__,y_test.__class__ )

model=Sequential()
model.add(Dense(6,activation="relu", input_shape=(10,)))
model.add(Dense(10,activation="softmax"))
model.build(input_shape=(None,1))
model.summary()
model.compile(optimizer='rmsprop',
              loss='binary_crossentropy',
              metrics=['accuracy'])
model.fit(x=X_train,
          y=y_train,
          epochs=600,
          validation_data=(X_test, y_test), verbose=1
          )

I have read my model is likely wrong in terms of input parameters, what is the correct approach?

Answer 1

As correctly mentioned by @MSS, You need to use sigmoid activation function with 1 neuron in the last dense layer to match the logits with the labels(1,0) of your dataset which indicates binary class.

Fixed code:

model=Sequential()
model.add(Dense(6,activation="relu", input_shape=(10,)))
model.add(Dense(1,activation="sigmoid"))
#model.build(input_shape=(None,1))
model.summary()

model.compile(optimizer='rmsprop',loss='binary_crossentropy',metrics=['accuracy'])

model.fit(x=X_train,y=y_train,epochs=10,validation_data=(X_test, y_test),verbose=1)

Output:

Epoch 1/10
446/446 [==============================] - 3s 4ms/step - loss: 0.5400 - accuracy: 0.7449 - val_loss: 0.4769 - val_accuracy: 0.7800
Epoch 2/10
446/446 [==============================] - 2s 4ms/step - loss: 0.4425 - accuracy: 0.7987 - val_loss: 0.4241 - val_accuracy: 0.8095
Epoch 3/10
446/446 [==============================] - 2s 3ms/step - loss: 0.4082 - accuracy: 0.8175 - val_loss: 0.4034 - val_accuracy: 0.8242
Epoch 4/10
446/446 [==============================] - 2s 3ms/step - loss: 0.3934 - accuracy: 0.8286 - val_loss: 0.3927 - val_accuracy: 0.8313
Epoch 5/10
446/446 [==============================] - 2s 4ms/step - loss: 0.3854 - accuracy: 0.8347 - val_loss: 0.3866 - val_accuracy: 0.8320
Epoch 6/10
446/446 [==============================] - 2s 4ms/step - loss: 0.3800 - accuracy: 0.8397 - val_loss: 0.3827 - val_accuracy: 0.8364
Epoch 7/10
446/446 [==============================] - 2s 4ms/step - loss: 0.3762 - accuracy: 0.8411 - val_loss: 0.3786 - val_accuracy: 0.8387
Epoch 8/10
446/446 [==============================] - 2s 3ms/step - loss: 0.3726 - accuracy: 0.8432 - val_loss: 0.3764 - val_accuracy: 0.8404
Epoch 9/10
446/446 [==============================] - 2s 3ms/step - loss: 0.3695 - accuracy: 0.8466 - val_loss: 0.3724 - val_accuracy: 0.8408
Epoch 10/10
446/446 [==============================] - 2s 4ms/step - loss: 0.3665 - accuracy: 0.8478 - val_loss: 0.3698 - val_accuracy: 0.8454
<keras.callbacks.History at 0x7f68ca30f670>