/* compute declination angle of sun and equation of time */
DoublePair sun_position(double jd)
{
double d = jd - 2451545.0;
double g = fix_angle(357.529 + 0.98560028 * d);
double q = fix_angle(280.459 + 0.98564736 * d);
double l = fix_angle(q + 1.915 * dsin(g) + 0.020 * dsin(2 * g));
// double r = 1.00014 - 0.01671 * dcos(g) - 0.00014 * dcos(2 * g);
double e = 23.439 - 0.00000036 * d;
double dd = darcsin(dsin(e) * dsin(l));
double ra = darctan2(dcos(e) * dsin(l), dcos(l)) / 15.0;
ra = fix_hour(ra);
double eq_t = q / 15.0 - ra;
return DoublePair(dd, eq_t);
}
void
d_scalar_scalar_1(void)
{
// d(x,x)?
if (equal(p1, p2)) {
push(one);
return;
}
// d(a,x)?
if (!iscons(p1)) {
push(zero);
return;
}
if (isadd(p1)) {
dsum();
return;
}
if (car(p1) == symbol(MULTIPLY)) {
dproduct();
return;
}
if (car(p1) == symbol(POWER)) {
dpower();
return;
}
if (car(p1) == symbol(DERIVATIVE)) {
dd();
return;
}
if (car(p1) == symbol(LOG)) {
dlog();
return;
}
if (car(p1) == symbol(SIN)) {
dsin();
return;
}
if (car(p1) == symbol(COS)) {
dcos();
return;
}
if (car(p1) == symbol(TAN)) {
dtan();
return;
}
if (car(p1) == symbol(ARCSIN)) {
darcsin();
return;
}
if (car(p1) == symbol(ARCCOS)) {
darccos();
return;
}
if (car(p1) == symbol(ARCTAN)) {
darctan();
return;
}
if (car(p1) == symbol(SINH)) {
dsinh();
return;
}
if (car(p1) == symbol(COSH)) {
dcosh();
return;
}
if (car(p1) == symbol(TANH)) {
dtanh();
return;
}
if (car(p1) == symbol(ARCSINH)) {
darcsinh();
return;
}
if (car(p1) == symbol(ARCCOSH)) {
darccosh();
return;
}
if (car(p1) == symbol(ARCTANH)) {
darctanh();
return;
}
if (car(p1) == symbol(ABS)) {
dabs();
return;
}
if (car(p1) == symbol(SGN)) {
dsgn();
return;
}
if (car(p1) == symbol(HERMITE)) {
dhermite();
return;
}
if (car(p1) == symbol(ERF)) {
derf();
return;
}
if (car(p1) == symbol(ERFC)) {
derfc();
return;
}
/*if (car(p1) == symbol(BESSELJ)) {
if (iszero(caddr(p1)))
dbesselj0();
else
dbesseljn();
return;
}*/
/*if (car(p1) == symbol(BESSELY)) {
if (iszero(caddr(p1)))
dbessely0();
else
dbesselyn();
return;
}*/
if (car(p1) == symbol(INTEGRAL) && caddr(p1) == p2) {
derivative_of_integral();
return;
}
dfunction();
}
