Python – tensorflow.math.confusion_matrix()

TensorFlow is open-source Python library designed by Google to develop Machine Learning models and deep learning  neural networks.  confusion_matrix() is used to find the confusion matrix from predictions and labels.

Syntax: tensorflow.math.confusion_matrix( labels, predictions, num_classes, weights, dtype,name)
 

Parameters:

• labels: It’s a 1-D Tensor which contains real labels for the classification task.
• predictions: It’s also a 1-D Tensor of same shape as labels. It’s value represents the predicted class.
• num_classes(optional): It is the possible number of labels/class classification task might have. If it’s not provided then num_classes will be one more than the maximum value in either predictions or labels.
• weight(optional): It’s a Tensor of same shape as predictions whose values define the corresponding weight for each prediction.
• dtype(optional): It defines the dtype of returned confusion matrix. Default if tensorflow.dtypes.int32.
• name(optional): Defines the name for the operation.
   

Returns:
It returns a confusion matrix of shape [n,n] where n is the possible number of labels.
 

Example 1:

Output:

labels:  tf.Tensor([1 3 4], shape=(3,), dtype=int32)
Predictions:  tf.Tensor([1 2 3], shape=(3,), dtype=int32)
Confusion_matrix:  tf.Tensor(
[[0 0 0 0 0]
 [0 1 0 0 0]
 [0 0 0 0 0]
 [0 0 1 0 0]
 [0 0 0 1 0]], shape=(5, 5), dtype=int32)

Example2: This example provide the weights to all predictions.

Output:

labels:  tf.Tensor([1 3 4], shape=(3,), dtype=int32)
Predictions:  tf.Tensor([1 2 4], shape=(3,), dtype=int32)
Weights:  tf.Tensor([1 2 2], shape=(3,), dtype=int32)
Confusion_matrix:  tf.Tensor(
[[0 0 0 0 0]
 [0 1 0 0 0]
 [0 0 0 0 0]
 [0 0 2 0 0]
 [0 0 0 0 2]], shape=(5, 5), dtype=int32)