tensorflow tf.argmax() 用法 例子

轉自：https://blog.csdn.net/Jiaach/article/details/78874704

argmax()官方文件如下：

tf.argmax(input, dimension, name=None) 
Returns the index with the largest value across dimensions of a tensor. 
Args: 
input: A Tensor. Must be one of the following types: float32, float64, int64, int32, uint8, int16, int8, complex64, qint8, quint8, qint32. 
dimension: A Tensor of type int32. int32, 0 <= dimension < rank(input). Describes which dimension of the input Tensor to reduce across. For vectors, use dimension = 0. 
name: A name for the operation (optional). 
Returns: 
A Tensor of type int64.

dimension=0 按列找 
dimension=1 按行找 
tf.argmax()返回最大數值的下標 
通常和tf.equal()一起使用，計算模型準確度

correct_pred = tf.equal(tf.argmax(pred,1), tf.argmax(y,1))
accuracy = tf.reduce_mean(tf.cast(correct_pred, tf.float32))

栗子

>>> import tensorflow as tf
>>> a = tf.constant([1.,2.,3.,0.,9.,])
>>> b = tf.constant([[1,2,3],[3,2,1],[4,5,6],[6,5,4]])
>>> with tf.Session() as sess:
...     sess.run(tf.argmax(a, 0))
Output:
4
>>> with tf.Session() as sess:
...     sess.run(tf.argmax(b, 0))
Output:
array([3, 2, 2])
>>> with tf.Session() as sess:
...     sess.run(tf.argmax(b, 1))
Output:
array([2, 0, 2, 0])

Ref： 
API文件

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