每个 epoch 的准确度都是从 0 而不是 1 开始

Question

How to plot graph in Keras stating from 1 instead of 0. I have trained a model for 20 epochs and the graph is showing epoch x-axis from 0 to 19.

Code:

  hist = model.fit(train_generator, validation_data=val_generator,  epochs=20, 
  batch_size=batchsize)

  plt.figure(figsize=(8,8))
  plt.subplot(2,1,1)

  plt.plot(hist.history['accuracy'],marker='o')
  plt.plot(hist.history['val_accuracy'],marker='p')
  plt.axis(ymin=0.0,ymax=1)
  plt.grid()
  plt.title('VGG16 Model Accuracy')
  plt.ylabel('Accuracy')
  plt.xlabel('Epochs')
  plt.legend(['Training Accuracy', 'Validation Accuracy'])
  plt.show()

How this problem could be resolved?

Answer 1

You can do like this:

import matplotlib.pyplot as plt
import numpy as np

acc_train_history = hist.history['accuracy']
acc_val_history = hist.history['val_accuracy']

plt.figure(figsize=(8,8))
plt.subplot(2,1,1)

plt.plot(acc_train_history, marker='o')
plt.plot(acc_val_history,marker='p')
# change the values on the ticks, starting from 1
plt.xticks(np.arange(len(acc_train_history)), np.arange(1, len(acc_train_history)+1))

plt.axis(ymin=0.0, ymax=1)
plt.grid()
plt.title('VGG16 Model Accuracy')
plt.ylabel('Accuracy')
plt.xlabel('Epochs')
plt.legend(['Training Accuracy', 'Validation Accuracy'])
plt.show()

Basically xticks lets you specify the labels that you want on your x axis.