| commit | 16b3675bc808095b81ee14dc4f89fb346ff1a0b0 | [log] [tgz] |
|---|---|---|
| author | Robert Griesemer <gri@golang.org> | Sat Sep 19 18:24:16 2015 -0700 |
| committer | Robert Griesemer <gri@golang.org> | Tue Sep 22 05:48:02 2015 +0000 |
| tree | ce91b4c358855e699c2dc1685c8417bdc0a21bf2 | |
| parent | c396c047c68ce59c67d1ee6d1f6756642b223bae [diff] |
math/big: optimize Float.Parse by reducing powers of 10 to powers of 2 and 5 Instead of computing the final adjustment factor as a power of 10, it's more efficient to split 10**e into 2**e * 5**e . Powers of 2 are trivially added to the Float exponent, and powers of 5 are smaller and thus faster to compute. Also, use a table of uint64 values rather than float64 values for initial power value. uint64 values appear to be faster to convert to Floats (useful for small exponents). Added two small benchmarks to confirm that there's no regresssion. benchmark old ns/op new ns/op delta BenchmarkParseFloatSmallExp-8 17543 16220 -7.54% BenchmarkParseFloatLargeExp-8 60865 59996 -1.43% Change-Id: I3efd7556b023316f86f334137a67fe0c6d52f8ef Reviewed-on: https://go-review.googlesource.com/14782 Reviewed-by: Alan Donovan <adonovan@google.com>
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