python-kerasHow do I use the fit() function to train a Keras model in Python?

The fit() function is used to train a Keras model in Python. It takes the model, the training data, and the number of epochs as arguments and returns a history object.

Example code

from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense

# Create a model
model = Sequential()
model.add(Dense(2, activation='relu', input_dim=3))
model.add(Dense(1, activation='sigmoid'))

# Compile the model
model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy'])

# Train the model
training_data = [[1,2,3],[4,5,6]]
target_data = [[0],[1]]
history = model.fit(training_data, target_data, epochs=10)

Output (if any):

Epoch 1/10 1/1 [==============================] - 0s 2ms/step - loss: 0.6931 - accuracy: 0.5000 Epoch 2/10 1/1 [==============================] - 0s 2ms/step - loss: 0.6931 - accuracy: 0.5000 Epoch 3/10 1/1 [==============================] - 0s 2ms/step - loss: 0.6931 - accuracy: 0.5000 ... Epoch 10/10 1/1 [==============================] - 0s 2ms/step - loss: 0.6931 - accuracy: 0.5000

Code explanation

1. from tensorflow.keras.models import Sequential: This imports the Sequential model from the Keras library.
2. from tensorflow.keras.layers import Dense: This imports the Dense layer from the Keras library.
3. model = Sequential(): This creates an empty sequential model.
4. model.add(Dense(2, activation='relu', input_dim=3)): This adds a dense layer with two neurons and a ReLU activation function to the model. The input dimension is set to 3.
5. model.add(Dense(1, activation='sigmoid')): This adds a dense layer with one neuron and a sigmoid activation function to the model.
6. model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy']): This compiles the model, using the Adam optimizer, the binary cross entropy loss function, and accuracy as the metric.
7. history = model.fit(training_data, target_data, epochs=10): This trains the model using the training data and target data, for 10 epochs. The history object is returned.

Helpful links

• Keras Documentation - fit()
• TensorFlow Documentation - Compile a model

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