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lib/libm/math: Make tanhf more efficient and handle large numbers. 

Prior to this patch tanhf(large number) would return nan due to inf/inf.
This commit is contained in:
Damien George 2018-09-04 16:59:08 +10:00
parent 0b239d458c
commit afc7ddca31
1 changed files with 7 additions and 3 deletions
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10
lib/libm/math.c
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@ -52,10 +52,14 @@ static const float _M_LN10 = 2.30258509299404; // 0x40135d8e
float log10f(float x) { return logf(x) / (float)_M_LN10; } float log10f(float x) { return logf(x) / (float)_M_LN10; }
float tanhf(float x) { float tanhf(float x) {
if (isinf(x)) { int sign = 0;
return copysignf(1, x); if (x < 0) {
sign = 1;
x = -x;
} }
return sinhf(x) / coshf(x); x = expm1f(-2 * x);
x = x / (x + 2);
return sign ? x : -x;
} }
/*****************************************************************************/ /*****************************************************************************/