npair_loss

paddle.fluid.layers.loss. npair_loss ( anchor, positive, labels, l2_reg=0.002 ) [source]

Npair loss requires paired data. Npair loss has two parts: the first part is L2 regularizer on the embedding vector; the second part is cross entropy loss which takes the similarity matrix of anchor and positive as logits.

For more information, please refer to: Improved Deep Metric Learning with Multi class N pair Loss Objective

Parameters
  • anchor (Tensor) – embedding vector for the anchor image. shape=[batch_size, embedding_dims], the data type is float32 or float64.

  • positive (Tensor) – embedding vector for the positive image. shape=[batch_size, embedding_dims], the data type is float32 or float64.

  • labels (Tensor) – 1-D tensor. shape=[batch_size], the data type is float32 or float64 or int64.

  • l2_reg (float32) – L2 regularization term on embedding vector, default: 0.002.

Returns

A Tensor representing the npair loss, the data type is the same as anchor, the shape is [1].

Examples

import paddle

DATATYPE = "float32"

anchor = paddle.rand(shape=(18, 6), dtype=DATATYPE)
positive = paddle.rand(shape=(18, 6), dtype=DATATYPE)
labels = paddle.rand(shape=(18,), dtype=DATATYPE)

npair_loss = paddle.nn.functional.npair_loss(anchor, positive, labels, l2_reg = 0.002)
print(npair_loss)