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| author | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
|---|---|---|
| committer | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
| commit | 4abab5ad6c8465a7528ccdd5f49367da05f78bbd (patch) | |
| tree | ebf009bf1376a5a223a915bc27cbbd791a1316bc /src/math/logb.c | |
Initial version
Diffstat (limited to 'src/math/logb.c')
| -rw-r--r-- | src/math/logb.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/math/logb.c b/src/math/logb.c new file mode 100644 index 0000000..7f8bdfa --- /dev/null +++ b/src/math/logb.c @@ -0,0 +1,17 @@ +#include <math.h> + +/* +special cases: + logb(+-0) = -inf, and raise divbyzero + logb(+-inf) = +inf + logb(nan) = nan +*/ + +double logb(double x) +{ + if (!isfinite(x)) + return x * x; + if (x == 0) + return -1/(x*x); + return ilogb(x); +} |