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Tensorflow中的KNN - 使用Graph预测看不见的数据

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基于以下Tensorflow中的KNN示例 - 使用该图来“预测”某些看不见的数据的标签的最佳方法是什么?

from __future__ import print_function

import numpy as np
import tensorflow as tf

# Import MNIST data
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("/tmp/data/", one_hot=True)

# In this example, we limit mnist data
Xtr, Ytr = mnist.train.next_batch(5000) #5000 for training (nn candidates)
Xte, Yte = mnist.test.next_batch(200) #200 for testing

# tf Graph Input
xtr = tf.placeholder("float", [None, 784])
xte = tf.placeholder("float", [784])

# Nearest Neighbor calculation using L1 Distance
# Calculate L1 Distance
distance = tf.reduce_sum(tf.abs(tf.add(xtr, tf.negative(xte))), reduction_indices=1)
# Prediction: Get min distance index (Nearest neighbor)
pred = tf.arg_min(distance, 0)

accuracy = 0.

# Initializing the variables
init = tf.global_variables_initializer()

# Launch the graph
with tf.Session() as sess:
    sess.run(init)

    # loop over test data
    for i in range(len(Xte)):
        # Get nearest neighbor
        nn_index = sess.run(pred, feed_dict={xtr: Xtr, xte: Xte[i, :]})
        # Get nearest neighbor class label and compare it to its true label
        print("Test", i, "Prediction:", np.argmax(Ytr[nn_index]), \
            "True Class:", np.argmax(Yte[i]))
        # Calculate accuracy
        if np.argmax(Ytr[nn_index]) == np.argmax(Yte[i]):
            accuracy += 1./len(Xte)
    print("Done!")
    print("Accuracy:", accuracy)

1 回答

  • 3

    你可以通过将这些行附加到末尾,在“with tf.Session()as sess:”中 .

    # Generate new (unseen) data
    X, y = mnist.test.next_batch(1)
    
    # Compute index of new data
    nn_index = sess.run(pred, feed_dict={xtr: Xtr, xte: X[0, :]})
    
    # Print the computed prediction 
    print("Test", i, 
          "Prediction:", np.argmax(Ytr[nn_index]),
          "True Class:", np.argmax(y[0]))
    

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