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| author | Erik Schnetter <schnetter@gmail.com> | 2013-06-09 00:16:29 -0400 |
|---|---|---|
| committer | Erik Schnetter <schnetter@gmail.com> | 2013-06-09 00:16:29 -0400 |
| commit | 7e8e3bee8f9ae74e9d9cd9b4601f215c229335a5 (patch) | |
| tree | bc86580fe4b245b315db74f4f8c5ce493f136bfb /mathfuncs_convert.h | |
| parent | 039eafa275852004c3483ecee323527f90e6ac81 (diff) | |
| download | vecmathlib-7e8e3bee8f9ae74e9d9cd9b4601f215c229335a5.zip vecmathlib-7e8e3bee8f9ae74e9d9cd9b4601f215c229335a5.tar.gz | |
Implement nextafter
Diffstat (limited to 'mathfuncs_convert.h')
| -rw-r--r-- | mathfuncs_convert.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/mathfuncs_convert.h b/mathfuncs_convert.h index d11c700..841ded4 100644 --- a/mathfuncs_convert.h +++ b/mathfuncs_convert.h @@ -172,6 +172,23 @@ namespace vecmathlib { return r; } + // Next machine representable number from x in direction y + template<typename realvec_t> + realvec_t mathfuncs<realvec_t>::vml_nextafter(realvec_t x, realvec_t y) + { + realvec_t dir = y - x; + realvec_t offset = ldexp(RV(FP::epsilon()), ilogb(x)); + offset = copysign(offset, dir); + offset = ifthen(convert_bool(as_int(x) & IV(FP::mantissa_mask)) || + signbit(x) == signbit(offset), + offset, + offset * RV(0.5)); + realvec_t r = x + offset; + real_t smallest_pos = std::ldexp(FP::min(), -FP::mantissa_bits); + return ifthen(dir==RV(0.0), y, + ifthen(x==RV(0.0), copysign(RV(smallest_pos), dir), r)); + } + }; // namespace vecmathlib #endif // #ifndef MATHFUNCS_CONVERT_H |
