Update precision in the ONNX strided_slice, update precision of ToScalar #6272
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zhiics
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Aug 14, 2020
| @@ -374,7 +374,7 @@ inline bool IsEqualScalar(const Expr& a, const Expr& b) { | |||
| * \param i element index | |||
| * \return Converted scalar value. | |||
| */ | |||
| static inline double ToScalar(const runtime::NDArray& array, size_t i = 0) { | |||
| static inline long double ToScalar(const runtime::NDArray& array, size_t i = 0) { | |||
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Because a double only has 52 bits of mantissa, it can't store the full precision of an int64_t.
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So we get rounding errors if we pass in large int64_t values
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On x86, long double has 63 bits of mantissa and 1 bit of sign, just like int64. On PowerPC and ARM, it's a 128bit floating point with 106 bits of mantissa.
zhiics
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Aug 14, 2020
|
Thanks @mbrookhart |
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Aug 26, 2020
…lar (apache#6272) * Update precision in the ONNX strided_slice, update precision of ToScalar * fix tests
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…lar (apache#6272) * Update precision in the ONNX strided_slice, update precision of ToScalar * fix tests
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…lar (apache#6272) * Update precision in the ONNX strided_slice, update precision of ToScalar * fix tests
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…lar (apache#6272) * Update precision in the ONNX strided_slice, update precision of ToScalar * fix tests
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Fixes #6263
ToScalar was casting a 64 bit Int to a 64 bit float, which reduced precision too much. I switched things to use int64_t/long double where needed to keep precision.
Thanks!
cc: @kevinthesun @zhiics @yongwww @lixiaoquan