/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifndef TEST


double
libtellurian_transverse_radius_radians(double latitude)
{
	double a = LIBTELLURIAN_EQUATORIAL_RADIUS;
	double b = LIBTELLURIAN_POLAR_RADIUS;
	double neg_e2 = fma(b / a, b / a, -1.0);
	double s = sin(latitude);
	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