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| author | Mattias Andrée <m@maandree.se> | 2024-10-20 17:28:46 +0200 |
|---|---|---|
| committer | Mattias Andrée <m@maandree.se> | 2024-10-20 17:28:46 +0200 |
| commit | 09e6857ae73249bc7433f2971dcf291c70e4c766 (patch) | |
| tree | f07ef152c6372083ab87e2e4289c7ab8b1f2c1ad /libtellurian_transverse_radius_radians.c | |
| parent | Third commit (diff) | |
| download | libtellurian-09e6857ae73249bc7433f2971dcf291c70e4c766.tar.gz libtellurian-09e6857ae73249bc7433f2971dcf291c70e4c766.tar.bz2 libtellurian-09e6857ae73249bc7433f2971dcf291c70e4c766.tar.xz | |
Fourth commit
Signed-off-by: Mattias Andrée <m@maandree.se>
Diffstat (limited to '')
| -rw-r--r-- | libtellurian_transverse_radius_radians.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/libtellurian_transverse_radius_radians.c b/libtellurian_transverse_radius_radians.c index dae8f04..c4f80aa 100644 --- a/libtellurian_transverse_radius_radians.c +++ b/libtellurian_transverse_radius_radians.c @@ -1,5 +1,6 @@ /* See LICENSE file for copyright and license details. */ #include "common.h" +#ifndef TEST double @@ -7,8 +8,35 @@ libtellurian_transverse_radius_radians(double latitude) { double a = LIBTELLURIAN_EQUATORIAL_RADIUS; double b = LIBTELLURIAN_POLAR_RADIUS; - double f = 1.0 - b / a; - double neg_e2 = (f - 2.0) * f; + double neg_e2 = fma(b / a, b / a, -1.0); double s = sin(latitude); - return pow(fma(neg_e2, s * s, 1.0), -0.5); + return a * pow(fma(neg_e2, s * s, 1.0), -0.5); } + + +#else + + +static int +approx(double a, double b) +{ + return fabs(a - b) <= 1e-8 * (0.5 * (a + b)); +} + +int +main(void) +{ + ASSERT(libtellurian_transverse_radius_radians(0) == LIBTELLURIAN_EQUATORIAL_RADIUS); + ASSERT(approx(libtellurian_transverse_radius_radians(D180), LIBTELLURIAN_EQUATORIAL_RADIUS)); + ASSERT(approx(libtellurian_transverse_radius_radians(-D180), LIBTELLURIAN_EQUATORIAL_RADIUS)); + ASSERT(approx(libtellurian_transverse_radius_radians(D30), libtellurian_transverse_radius_radians(-D30))); + ASSERT(approx(libtellurian_transverse_radius_radians(D45), libtellurian_transverse_radius_radians(-D45))); + ASSERT(approx(libtellurian_transverse_radius_radians(D60), libtellurian_transverse_radius_radians(-D60))); + ASSERT(approx(libtellurian_transverse_radius_radians(D90), libtellurian_transverse_radius_radians(-D90))); + ASSERT(fabs(libtellurian_transverse_radius_radians(D90) - 6399593.625758674) / 6399593.625758674 < 1.0e-8); + ASSERT(fabs(libtellurian_transverse_radius_radians(D30) - 6383480.917690154) / 6383480.917690154 < 1.0e-8); + return 0; +} + + +#endif |