fix the bug in sigmoid_cross_entropy_with_logits_grad_kernel #64253
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你的PR提交成功，感谢你对开源项目的贡献! |
| T up = -e_x * abs_grad * pos_weight; | ||
| T term3 = up / down; | ||
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| T diff = term1 - label + term3; |
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补充相关单侧 |
Done |
Aurelius84
reviewed
May 16, 2024
| T diff = simoid_x * pos_weight_idx - label; | ||
| T term1 = (x > 0) ? static_cast<T>(1) : static_cast<T>(0); | ||
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| T e_x = std::exp(-std::abs(x)); |
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这里为什么要加 std::abs(x) ? e_x 变量不是指的e^(-x) 么?
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这是根据前向计算的求导得到的，前向计算是$e^{-|X|}$，其导数是$-e^{-|x|} * where(x>=0,1,0)$
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因为前向中的e^x是e^-abs(x)，所以反向也需要保持e^-abs(x)
Aurelius84
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May 16, 2024
co63oc
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May 18, 2024
…addle#64253) * fix the bug in sigmoid_cross_entropy_with_logits_grad_kernel * add the test for sigmoid_cross_entropy_with_logits_grad * modify the test * modify the grad kernel * modify the kernel
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PR Category
Others
PR Types
Bug fixes
Description
sigmoid_cross_entropy_with_logitsop的反向kernel计算实现，与自动微分求导计算出的反向结果不一致。现提交PR进行修复，具体分析以及反向kernel计算方式错误仍能通过单测的分析见下面的Issue：