multinomial¶

paddle. multinomial ( x, num_samples=1, replacement=False, name=None ) [source]

Returns a Tensor filled with random values sampled from a Multinomical distribution. The input x is a tensor with probabilities for generating the random number. Each element in x should be larger or equal to 0, but not all 0. replacement indicates whether it is a replaceable sample. If replacement is True, a category can be sampled more than once.

Parameters

• x (Tensor) – A tensor with probabilities for generating the random number. The data type should be float32, float64.

• num_samples (int, optional) – Number of samples, default is 1.

• replacement (bool, optional) – Whether it is a replaceable sample, default is False.

• name (str, optional) – The default value is None. Normally there is no need for user to set this property. For more information, please refer to Name.

Returns

A Tensor filled with sampled category index after num_samples times samples.

Return type

Tensor

Examples

import paddle

paddle.seed(100) # on CPU device
x = paddle.rand([2,4])
print(x)
# [[0.5535528  0.20714243 0.01162981 0.51577556]
# [0.36369765 0.2609165  0.18905126 0.5621971 ]]

paddle.seed(200) # on CPU device
out1 = paddle.multinomial(x, num_samples=5, replacement=True)
print(out1)
# [[3 3 0 0 0]
# [3 3 3 1 0]]

# out2 = paddle.multinomial(x, num_samples=5)
# InvalidArgumentError: When replacement is False, number of samples
#  should be less than non-zero categories

paddle.seed(300) # on CPU device
out3 = paddle.multinomial(x, num_samples=3)
print(out3)
# [[3 0 1]
# [3 1 0]]