[Bug fixes]fix bce error when option pos_weight given

[LielinJiang]

PR Category

Operator Mechanism

PR Types

Bug fixes

Description

binary_cross_entropy get wrong value when pos_weight option was given. Here is an example:

logit = paddle.to_tensor([-14.913008])
label = paddle.to_tensor([1.0])

output = paddle.nn.functional.binary_cross_entropy_with_logits(logit, label, reduction='none', pos_weight=paddle.to_tensor(3.0))
# we expect to get ouput=44.73, but got 14.913

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[DesmonDay]

LGTM