correct copysign backward #74322
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correct copysign backward #74322
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lshpku reviewed Jul 31, 2025
| if (x == static_cast<InT>(0)) | ||
| outs[0] = static_cast<OutT>(0); | ||
| else | ||
| outs[0] = static_cast<OutT>(dout * (funcs::copysign_func(x, y)) / x); |
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这样改有依据吗？比如看下torch是这样改的吗？我怎么感觉这样改虽然解决了下溢问题但可能带来新的精度问题
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这样修改的一个依据是这个kernel的原作者针对copysign的反向写了3个GradFunctor，在CopySignGradXFunctor和CopySignGradXYFunctor中，对于x的求导顺序出现了差别，说明是作者在编程时错写了CopySignGradXYFunctor针对X的求导，将右括号放错了位置。
当然，我们可以参考torch的实现。
同样是先除再乘。
wangyuwen1999 changed the title wangyuwen1999 changed the title lshpku approved these changes Aug 8, 2025
Enigmatisms pushed a commit to Enigmatisms/Paddle that referenced this pull request Aug 11, 2025
* correct copysign backward * correct codestyle
maxiaolong001 pushed a commit to maxiaolong001/Paddle that referenced this pull request Aug 12, 2025
* correct copysign backward * correct codestyle
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PR Category
Operator Mechanism
PR Types
Bug fixes
Description
paddle.copysign对于大tensor的问题修复