JD
ymd2jd(YMD ymd)
{
JD jd;
int m, y;
y = ymdGetYear(ymd);
m = ymdGetMonth(ymd);
/* normalize the month */
if (m < 1) {
y -= (1 - m) / 12;
m = (m % 12) + 12;
}
if (m > 12) {
y += (m - 1) / 12;
m = ((m - 1) % 12) + 1;
}
jdSetDay(jd, gcal2j(y, m, 0));
jdIncDay(jd, ymdGetDay(ymd));
/* now the fractional day... */
jd.hms = ymd.hms;
/* julian days start 12 hours after civil days */
jdDecHours(jd, 12.0);
return(jd);
}
double
ymd2dd(YMD ymd)
{
double dd;
double j0;
double j;
/* normalize the time */
ymd = ymd2ymd(ymd);
/* get the julian day number of the target date */
j = ymd2j(ymd);
/* get the julian day number of the start of the year */
j0 = gcal2j(ymdGetYear(ymd), 1, 1) - 0.5;
dd = j - j0 + 1;
return(dd);
}
