diff options
Diffstat (limited to 'winsup/mingw/mingwex/complex/catanf.c')
-rwxr-xr-x | winsup/mingw/mingwex/complex/catanf.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/winsup/mingw/mingwex/complex/catanf.c b/winsup/mingw/mingwex/complex/catanf.c new file mode 100755 index 000000000..adddde885 --- /dev/null +++ b/winsup/mingw/mingwex/complex/catanf.c @@ -0,0 +1,49 @@ +/* catanf.c */ + +/* + Contributed by Danny Smith + 2004-12-24 + + FIXME: This needs some serious numerical analysis. +*/ + +#include <math.h> +#include <complex.h> +#include <errno.h> + +/* catan (z) = -I/2 * clog ((I + z) / (I - z)) */ + +float complex +catanf (float complex Z) +{ + float complex Res; + float complex Tmp; + float x = __real__ Z; + float y = __imag__ Z; + + if ( x == 0.0f && (1.0f - fabsf (y)) == 0.0f) + { + errno = ERANGE; + __real__ Res = HUGE_VALF; + __imag__ Res = HUGE_VALF; + } + else if (isinf (hypotf (x, y))) + { + __real__ Res = (x > 0 ? M_PI_2 : -M_PI_2); + __imag__ Res = 0.0f; + } + else + { + __real__ Tmp = - x; + __imag__ Tmp = 1.0f - y; + + __real__ Res = x; + __imag__ Res = y + 1.0f; + + Tmp = clogf (Res/Tmp); + __real__ Res = - 0.5f * __imag__ Tmp; + __imag__ Res = 0.5f * __real__ Tmp; + } + + return Res; +} |