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| author | nsz <nsz@port70.net> | 2012-05-05 01:11:56 +0200 |
|---|---|---|
| committer | nsz <nsz@port70.net> | 2012-05-05 01:11:56 +0200 |
| commit | f697d66b81912af59128ac1b96bc0e2a4514b758 (patch) | |
| tree | 32433a4df7d33f692afa2ff6e759fa1c5870b8f0 /src/string/memchr.c | |
| parent | db4096c5f2ffb15e52015004ab5a900b820c6683 (diff) | |
| download | musl-f697d66b81912af59128ac1b96bc0e2a4514b758.tar.gz | |
math: change the formula used for acos.s
old: 2*atan2(sqrt(1-x),sqrt(1+x))
new: atan2(fabs(sqrt((1-x)*(1+x))),x)
improvements:
* all edge cases are fixed (sign of zero in downward rounding)
* a bit faster (here a single call is about 131ns vs 162ns)
* a bit more precise (at most 1ulp error on 1M uniform random
samples in [0,1), the old formula gave some 2ulp errors as well)
Diffstat (limited to 'src/string/memchr.c')
0 files changed, 0 insertions, 0 deletions