diff options
Diffstat (limited to 'deps/icu-small/source/i18n/astro.cpp')
| -rw-r--r-- | deps/icu-small/source/i18n/astro.cpp | 1601 |
1 files changed, 1601 insertions, 0 deletions
diff --git a/deps/icu-small/source/i18n/astro.cpp b/deps/icu-small/source/i18n/astro.cpp new file mode 100644 index 0000000000..1b3bf58964 --- /dev/null +++ b/deps/icu-small/source/i18n/astro.cpp @@ -0,0 +1,1601 @@ +/************************************************************************ + * Copyright (C) 1996-2012, International Business Machines Corporation + * and others. All Rights Reserved. + ************************************************************************ + * 2003-nov-07 srl Port from Java + */ + +#include "astro.h" + +#if !UCONFIG_NO_FORMATTING + +#include "unicode/calendar.h" +#include <math.h> +#include <float.h> +#include "unicode/putil.h" +#include "uhash.h" +#include "umutex.h" +#include "ucln_in.h" +#include "putilimp.h" +#include <stdio.h> // for toString() + +#if defined (PI) +#undef PI +#endif + +#ifdef U_DEBUG_ASTRO +# include "uresimp.h" // for debugging + +static void debug_astro_loc(const char *f, int32_t l) +{ + fprintf(stderr, "%s:%d: ", f, l); +} + +static void debug_astro_msg(const char *pat, ...) +{ + va_list ap; + va_start(ap, pat); + vfprintf(stderr, pat, ap); + fflush(stderr); +} +#include "unicode/datefmt.h" +#include "unicode/ustring.h" +static const char * debug_astro_date(UDate d) { + static char gStrBuf[1024]; + static DateFormat *df = NULL; + if(df == NULL) { + df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS()); + df->adoptTimeZone(TimeZone::getGMT()->clone()); + } + UnicodeString str; + df->format(d,str); + u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1); + return gStrBuf; +} + +// must use double parens, i.e.: U_DEBUG_ASTRO_MSG(("four is: %d",4)); +#define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;} +#else +#define U_DEBUG_ASTRO_MSG(x) +#endif + +static inline UBool isINVALID(double d) { + return(uprv_isNaN(d)); +} + +static UMutex ccLock = U_MUTEX_INITIALIZER; + +U_CDECL_BEGIN +static UBool calendar_astro_cleanup(void) { + return TRUE; +} +U_CDECL_END + +U_NAMESPACE_BEGIN + +/** + * The number of standard hours in one sidereal day. + * Approximately 24.93. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define SIDEREAL_DAY (23.93446960027) + +/** + * The number of sidereal hours in one mean solar day. + * Approximately 24.07. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define SOLAR_DAY (24.065709816) + +/** + * The average number of solar days from one new moon to the next. This is the time + * it takes for the moon to return the same ecliptic longitude as the sun. + * It is longer than the sidereal month because the sun's longitude increases + * during the year due to the revolution of the earth around the sun. + * Approximately 29.53. + * + * @see #SIDEREAL_MONTH + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +const double CalendarAstronomer::SYNODIC_MONTH = 29.530588853; + +/** + * The average number of days it takes + * for the moon to return to the same ecliptic longitude relative to the + * stellar background. This is referred to as the sidereal month. + * It is shorter than the synodic month due to + * the revolution of the earth around the sun. + * Approximately 27.32. + * + * @see #SYNODIC_MONTH + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define SIDEREAL_MONTH 27.32166 + +/** + * The average number number of days between successive vernal equinoxes. + * Due to the precession of the earth's + * axis, this is not precisely the same as the sidereal year. + * Approximately 365.24 + * + * @see #SIDEREAL_YEAR + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define TROPICAL_YEAR 365.242191 + +/** + * The average number of days it takes + * for the sun to return to the same position against the fixed stellar + * background. This is the duration of one orbit of the earth about the sun + * as it would appear to an outside observer. + * Due to the precession of the earth's + * axis, this is not precisely the same as the tropical year. + * Approximately 365.25. + * + * @see #TROPICAL_YEAR + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define SIDEREAL_YEAR 365.25636 + +//------------------------------------------------------------------------- +// Time-related constants +//------------------------------------------------------------------------- + +/** + * The number of milliseconds in one second. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define SECOND_MS U_MILLIS_PER_SECOND + +/** + * The number of milliseconds in one minute. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define MINUTE_MS U_MILLIS_PER_MINUTE + +/** + * The number of milliseconds in one hour. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define HOUR_MS U_MILLIS_PER_HOUR + +/** + * The number of milliseconds in one day. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define DAY_MS U_MILLIS_PER_DAY + +/** + * The start of the julian day numbering scheme used by astronomers, which + * is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds + * since 1/1/1970 AD (Gregorian), a negative number. + * Note that julian day numbers and + * the Julian calendar are <em>not</em> the same thing. Also note that + * julian days start at <em>noon</em>, not midnight. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +#define JULIAN_EPOCH_MS -210866760000000.0 + + +/** + * Milliseconds value for 0.0 January 2000 AD. + */ +#define EPOCH_2000_MS 946598400000.0 + +//------------------------------------------------------------------------- +// Assorted private data used for conversions +//------------------------------------------------------------------------- + +// My own copies of these so compilers are more likely to optimize them away +const double CalendarAstronomer::PI = 3.14159265358979323846; + +#define CalendarAstronomer_PI2 (CalendarAstronomer::PI*2.0) +#define RAD_HOUR ( 12 / CalendarAstronomer::PI ) // radians -> hours +#define DEG_RAD ( CalendarAstronomer::PI / 180 ) // degrees -> radians +#define RAD_DEG ( 180 / CalendarAstronomer::PI ) // radians -> degrees + +/*** + * Given 'value', add or subtract 'range' until 0 <= 'value' < range. + * The modulus operator. + */ +inline static double normalize(double value, double range) { + return value - range * ClockMath::floorDivide(value, range); +} + +/** + * Normalize an angle so that it's in the range 0 - 2pi. + * For positive angles this is just (angle % 2pi), but the Java + * mod operator doesn't work that way for negative numbers.... + */ +inline static double norm2PI(double angle) { + return normalize(angle, CalendarAstronomer::PI * 2.0); +} + +/** + * Normalize an angle into the range -PI - PI + */ +inline static double normPI(double angle) { + return normalize(angle + CalendarAstronomer::PI, CalendarAstronomer::PI * 2.0) - CalendarAstronomer::PI; +} + +//------------------------------------------------------------------------- +// Constructors +//------------------------------------------------------------------------- + +/** + * Construct a new <code>CalendarAstronomer</code> object that is initialized to + * the current date and time. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::CalendarAstronomer(): + fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) { + clearCache(); +} + +/** + * Construct a new <code>CalendarAstronomer</code> object that is initialized to + * the specified date and time. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) { + clearCache(); +} + +/** + * Construct a new <code>CalendarAstronomer</code> object with the given + * latitude and longitude. The object's time is set to the current + * date and time. + * <p> + * @param longitude The desired longitude, in <em>degrees</em> east of + * the Greenwich meridian. + * + * @param latitude The desired latitude, in <em>degrees</em>. Positive + * values signify North, negative South. + * + * @see java.util.Date#getTime() + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) : + fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) { + fLongitude = normPI(longitude * (double)DEG_RAD); + fLatitude = normPI(latitude * (double)DEG_RAD); + fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2); + clearCache(); +} + +CalendarAstronomer::~CalendarAstronomer() +{ +} + +//------------------------------------------------------------------------- +// Time and date getters and setters +//------------------------------------------------------------------------- + +/** + * Set the current date and time of this <code>CalendarAstronomer</code> object. All + * astronomical calculations are performed based on this time setting. + * + * @param aTime the date and time, expressed as the number of milliseconds since + * 1/1/1970 0:00 GMT (Gregorian). + * + * @see #setDate + * @see #getTime + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +void CalendarAstronomer::setTime(UDate aTime) { + fTime = aTime; + U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset))); + clearCache(); +} + +/** + * Set the current date and time of this <code>CalendarAstronomer</code> object. All + * astronomical calculations are performed based on this time setting. + * + * @param jdn the desired time, expressed as a "julian day number", + * which is the number of elapsed days since + * 1/1/4713 BC (Julian), 12:00 GMT. Note that julian day + * numbers start at <em>noon</em>. To get the jdn for + * the corresponding midnight, subtract 0.5. + * + * @see #getJulianDay + * @see #JULIAN_EPOCH_MS + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +void CalendarAstronomer::setJulianDay(double jdn) { + fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS; + clearCache(); + julianDay = jdn; +} + +/** + * Get the current time of this <code>CalendarAstronomer</code> object, + * represented as the number of milliseconds since + * 1/1/1970 AD 0:00 GMT (Gregorian). + * + * @see #setTime + * @see #getDate + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +UDate CalendarAstronomer::getTime() { + return fTime; +} + +/** + * Get the current time of this <code>CalendarAstronomer</code> object, + * expressed as a "julian day number", which is the number of elapsed + * days since 1/1/4713 BC (Julian), 12:00 GMT. + * + * @see #setJulianDay + * @see #JULIAN_EPOCH_MS + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getJulianDay() { + if (isINVALID(julianDay)) { + julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS; + } + return julianDay; +} + +/** + * Return this object's time expressed in julian centuries: + * the number of centuries after 1/1/1900 AD, 12:00 GMT + * + * @see #getJulianDay + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getJulianCentury() { + if (isINVALID(julianCentury)) { + julianCentury = (getJulianDay() - 2415020.0) / 36525.0; + } + return julianCentury; +} + +/** + * Returns the current Greenwich sidereal time, measured in hours + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getGreenwichSidereal() { + if (isINVALID(siderealTime)) { + // See page 86 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + + double UT = normalize(fTime/(double)HOUR_MS, 24.); + + siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.); + } + return siderealTime; +} + +double CalendarAstronomer::getSiderealOffset() { + if (isINVALID(siderealT0)) { + double JD = uprv_floor(getJulianDay() - 0.5) + 0.5; + double S = JD - 2451545.0; + double T = S / 36525.0; + siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24); + } + return siderealT0; +} + +/** + * Returns the current local sidereal time, measured in hours + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getLocalSidereal() { + return normalize(getGreenwichSidereal() + (fGmtOffset/(double)HOUR_MS), 24.); +} + +/** + * Converts local sidereal time to Universal Time. + * + * @param lst The Local Sidereal Time, in hours since sidereal midnight + * on this object's current date. + * + * @return The corresponding Universal Time, in milliseconds since + * 1 Jan 1970, GMT. + */ +double CalendarAstronomer::lstToUT(double lst) { + // Convert to local mean time + double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24); + + // Then find local midnight on this day + double base = (DAY_MS * ClockMath::floorDivide(fTime + fGmtOffset,(double)DAY_MS)) - fGmtOffset; + + //out(" lt =" + lt + " hours"); + //out(" base=" + new Date(base)); + + return base + (long)(lt * HOUR_MS); +} + + +//------------------------------------------------------------------------- +// Coordinate transformations, all based on the current time of this object +//------------------------------------------------------------------------- + +/** + * Convert from ecliptic to equatorial coordinates. + * + * @param ecliptic A point in the sky in ecliptic coordinates. + * @return The corresponding point in equatorial coordinates. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic) +{ + return eclipticToEquatorial(result, ecliptic.longitude, ecliptic.latitude); +} + +/** + * Convert from ecliptic to equatorial coordinates. + * + * @param eclipLong The ecliptic longitude + * @param eclipLat The ecliptic latitude + * + * @return The corresponding point in equatorial coordinates. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat) +{ + // See page 42 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + + double obliq = eclipticObliquity(); + double sinE = ::sin(obliq); + double cosE = cos(obliq); + + double sinL = ::sin(eclipLong); + double cosL = cos(eclipLong); + + double sinB = ::sin(eclipLat); + double cosB = cos(eclipLat); + double tanB = tan(eclipLat); + + result.set(atan2(sinL*cosE - tanB*sinE, cosL), + asin(sinB*cosE + cosB*sinE*sinL) ); + return result; +} + +/** + * Convert from ecliptic longitude to equatorial coordinates. + * + * @param eclipLong The ecliptic longitude + * + * @return The corresponding point in equatorial coordinates. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong) +{ + return eclipticToEquatorial(result, eclipLong, 0); // TODO: optimize +} + +/** + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong) +{ + Equatorial equatorial; + eclipticToEquatorial(equatorial, eclipLong); + + double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension; // Hour-angle + + double sinH = ::sin(H); + double cosH = cos(H); + double sinD = ::sin(equatorial.declination); + double cosD = cos(equatorial.declination); + double sinL = ::sin(fLatitude); + double cosL = cos(fLatitude); + + double altitude = asin(sinD*sinL + cosD*cosL*cosH); + double azimuth = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude)); + + result.set(azimuth, altitude); + return result; +} + + +//------------------------------------------------------------------------- +// The Sun +//------------------------------------------------------------------------- + +// +// Parameters of the Sun's orbit as of the epoch Jan 0.0 1990 +// Angles are in radians (after multiplying by CalendarAstronomer::PI/180) +// +#define JD_EPOCH 2447891.5 // Julian day of epoch + +#define SUN_ETA_G (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch +#define SUN_OMEGA_G (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee +#define SUN_E 0.016713 // Eccentricity of orbit +//double sunR0 1.495585e8 // Semi-major axis in KM +//double sunTheta0 (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0 + +// The following three methods, which compute the sun parameters +// given above for an arbitrary epoch (whatever time the object is +// set to), make only a small difference as compared to using the +// above constants. E.g., Sunset times might differ by ~12 +// seconds. Furthermore, the eta-g computation is befuddled by +// Duffet-Smith's incorrect coefficients (p.86). I've corrected +// the first-order coefficient but the others may be off too - no +// way of knowing without consulting another source. + +// /** +// * Return the sun's ecliptic longitude at perigee for the current time. +// * See Duffett-Smith, p. 86. +// * @return radians +// */ +// private double getSunOmegaG() { +// double T = getJulianCentury(); +// return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD; +// } + +// /** +// * Return the sun's ecliptic longitude for the current time. +// * See Duffett-Smith, p. 86. +// * @return radians +// */ +// private double getSunEtaG() { +// double T = getJulianCentury(); +// //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD; +// // +// // The above line is from Duffett-Smith, and yields manifestly wrong +// // results. The below constant is derived empirically to match the +// // constant he gives for the 1990 EPOCH. +// // +// return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD; +// } + +// /** +// * Return the sun's eccentricity of orbit for the current time. +// * See Duffett-Smith, p. 86. +// * @return double +// */ +// private double getSunE() { +// double T = getJulianCentury(); +// return 0.01675104 - (0.0000418 + 0.000000126*T)*T; +// } + +/** + * Find the "true anomaly" (longitude) of an object from + * its mean anomaly and the eccentricity of its orbit. This uses + * an iterative solution to Kepler's equation. + * + * @param meanAnomaly The object's longitude calculated as if it were in + * a regular, circular orbit, measured in radians + * from the point of perigee. + * + * @param eccentricity The eccentricity of the orbit + * + * @return The true anomaly (longitude) measured in radians + */ +static double trueAnomaly(double meanAnomaly, double eccentricity) +{ + // First, solve Kepler's equation iteratively + // Duffett-Smith, p.90 + double delta; + double E = meanAnomaly; + do { + delta = E - eccentricity * ::sin(E) - meanAnomaly; + E = E - delta / (1 - eccentricity * ::cos(E)); + } + while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad + + return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity) + /(1-eccentricity) ) ); +} + +/** + * The longitude of the sun at the time specified by this object. + * The longitude is measured in radians along the ecliptic + * from the "first point of Aries," the point at which the ecliptic + * crosses the earth's equatorial plane at the vernal equinox. + * <p> + * Currently, this method uses an approximation of the two-body Kepler's + * equation for the earth and the sun. It does not take into account the + * perturbations caused by the other planets, the moon, etc. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getSunLongitude() +{ + // See page 86 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + + if (isINVALID(sunLongitude)) { + getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun); + } + return sunLongitude; +} + +/** + * TODO Make this public when the entire class is package-private. + */ +/*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly) +{ + // See page 86 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + + double day = jDay - JD_EPOCH; // Days since epoch + + // Find the angular distance the sun in a fictitious + // circular orbit has travelled since the epoch. + double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day); + + // The epoch wasn't at the sun's perigee; find the angular distance + // since perigee, which is called the "mean anomaly" + meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G); + + // Now find the "true anomaly", e.g. the real solar longitude + // by solving Kepler's equation for an elliptical orbit + // NOTE: The 3rd ed. of the book lists omega_g and eta_g in different + // equations; omega_g is to be correct. + longitude = norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G); +} + +/** + * The position of the sun at this object's current date and time, + * in equatorial coordinates. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) { + return eclipticToEquatorial(result, getSunLongitude(), 0); +} + + +/** + * Constant representing the vernal equinox. + * For use with {@link #getSunTime getSunTime}. + * Note: In this case, "vernal" refers to the northern hemisphere's seasons. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +/*double CalendarAstronomer::VERNAL_EQUINOX() { + return 0; +}*/ + +/** + * Constant representing the summer solstice. + * For use with {@link #getSunTime getSunTime}. + * Note: In this case, "summer" refers to the northern hemisphere's seasons. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::SUMMER_SOLSTICE() { + return (CalendarAstronomer::PI/2); +} + +/** + * Constant representing the autumnal equinox. + * For use with {@link #getSunTime getSunTime}. + * Note: In this case, "autumn" refers to the northern hemisphere's seasons. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +/*double CalendarAstronomer::AUTUMN_EQUINOX() { + return (CalendarAstronomer::PI); +}*/ + +/** + * Constant representing the winter solstice. + * For use with {@link #getSunTime getSunTime}. + * Note: In this case, "winter" refers to the northern hemisphere's seasons. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::WINTER_SOLSTICE() { + return ((CalendarAstronomer::PI*3)/2); +} + +CalendarAstronomer::AngleFunc::~AngleFunc() {} + +/** + * Find the next time at which the sun's ecliptic longitude will have + * the desired value. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc { +public: + virtual ~SunTimeAngleFunc(); + virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); } +}; + +SunTimeAngleFunc::~SunTimeAngleFunc() {} + +UDate CalendarAstronomer::getSunTime(double desired, UBool next) +{ + SunTimeAngleFunc func; + return timeOfAngle( func, + desired, + TROPICAL_YEAR, + MINUTE_MS, + next); +} + +CalendarAstronomer::CoordFunc::~CoordFunc() {} + +class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc { +public: + virtual ~RiseSetCoordFunc(); + virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { a.getSunPosition(result); } +}; + +RiseSetCoordFunc::~RiseSetCoordFunc() {} + +UDate CalendarAstronomer::getSunRiseSet(UBool rise) +{ + UDate t0 = fTime; + + // Make a rough guess: 6am or 6pm local time on the current day + double noon = ClockMath::floorDivide(fTime + fGmtOffset, (double)DAY_MS)*DAY_MS - fGmtOffset + (12*HOUR_MS); + + U_DEBUG_ASTRO_MSG(("Noon=%.2lf, %sL, gmtoff %.2lf\n", noon, debug_astro_date(noon+fGmtOffset), fGmtOffset)); + setTime(noon + ((rise ? -6 : 6) * HOUR_MS)); + U_DEBUG_ASTRO_MSG(("added %.2lf ms as a guess,\n", ((rise ? -6. : 6.) * HOUR_MS))); + + RiseSetCoordFunc func; + double t = riseOrSet(func, + rise, + .533 * DEG_RAD, // Angular Diameter + 34. /60.0 * DEG_RAD, // Refraction correction + MINUTE_MS / 12.); // Desired accuracy + + setTime(t0); + return t; +} + +// Commented out - currently unused. ICU 2.6, Alan +// //------------------------------------------------------------------------- +// // Alternate Sun Rise/Set +// // See Duffett-Smith p.93 +// //------------------------------------------------------------------------- +// +// // This yields worse results (as compared to USNO data) than getSunRiseSet(). +// /** +// * TODO Make this when the entire class is package-private. +// */ +// /*public*/ long getSunRiseSet2(boolean rise) { +// // 1. Calculate coordinates of the sun's center for midnight +// double jd = uprv_floor(getJulianDay() - 0.5) + 0.5; +// double[] sl = getSunLongitude(jd);// double lambda1 = sl[0]; +// Equatorial pos1 = eclipticToEquatorial(lambda1, 0); +// +// // 2. Add ... to lambda to get position 24 hours later +// double lambda2 = lambda1 + 0.985647*DEG_RAD; +// Equatorial pos2 = eclipticToEquatorial(lambda2, 0); +// +// // 3. Calculate LSTs of rising and setting for these two positions +// double tanL = ::tan(fLatitude); +// double H = ::acos(-tanL * ::tan(pos1.declination)); +// double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2; +// double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2; +// H = ::acos(-tanL * ::tan(pos2.declination)); +// double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2; +// double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2; +// if (lst1r > 24) lst1r -= 24; +// if (lst1s > 24) lst1s -= 24; +// if (lst2r > 24) lst2r -= 24; +// if (lst2s > 24) lst2s -= 24; +// +// // 4. Convert LSTs to GSTs. If GST1 > GST2, add 24 to GST2. +// double gst1r = lstToGst(lst1r); +// double gst1s = lstToGst(lst1s); +// double gst2r = lstToGst(lst2r); +// double gst2s = lstToGst(lst2s); +// if (gst1r > gst2r) gst2r += 24; +// if (gst1s > gst2s) gst2s += 24; +// +// // 5. Calculate GST at 0h UT of this date +// double t00 = utToGst(0); +// +// // 6. Calculate GST at 0h on the observer's longitude +// double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg. +// double t00p = t00 - offset*1.002737909; +// if (t00p < 0) t00p += 24; // do NOT normalize +// +// // 7. Adjust +// if (gst1r < t00p) { +// gst1r += 24; +// gst2r += 24; +// } +// if (gst1s < t00p) { +// gst1s += 24; +// gst2s += 24; +// } +// +// // 8. +// double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r); +// double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s); +// +// // 9. Correct for parallax, refraction, and sun's diameter +// double dec = (pos1.declination + pos2.declination) / 2; +// double psi = ::acos(sin(fLatitude) / cos(dec)); +// double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter +// double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG; +// double delta_t = 240 * y / cos(dec) / 3600; // hours +// +// // 10. Add correction to GSTs, subtract from GSTr +// gstr -= delta_t; +// gsts += delta_t; +// +// // 11. Convert GST to UT and then to local civil time +// double ut = gstToUt(rise ? gstr : gsts); +// //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t); +// long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day +// return midnight + (long) (ut * 3600000); +// } + +// Commented out - currently unused. ICU 2.6, Alan +// /** +// * Convert local sidereal time to Greenwich sidereal time. +// * Section 15. Duffett-Smith p.21 +// * @param lst in hours (0..24) +// * @return GST in hours (0..24) +// */ +// double lstToGst(double lst) { +// double delta = fLongitude * 24 / CalendarAstronomer_PI2; +// return normalize(lst - delta, 24); +// } + +// Commented out - currently unused. ICU 2.6, Alan +// /** +// * Convert UT to GST on this date. +// * Section 12. Duffett-Smith p.17 +// * @param ut in hours +// * @return GST in hours +// */ +// double utToGst(double ut) { +// return normalize(getT0() + ut*1.002737909, 24); +// } + +// Commented out - currently unused. ICU 2.6, Alan +// /** +// * Convert GST to UT on this date. +// * Section 13. Duffett-Smith p.18 +// * @param gst in hours +// * @return UT in hours +// */ +// double gstToUt(double gst) { +// return normalize(gst - getT0(), 24) * 0.9972695663; +// } + +// Commented out - currently unused. ICU 2.6, Alan +// double getT0() { +// // Common computation for UT <=> GST +// +// // Find JD for 0h UT +// double jd = uprv_floor(getJulianDay() - 0.5) + 0.5; +// +// double s = jd - 2451545.0; +// double t = s / 36525.0; +// double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t; +// return t0; +// } + +// Commented out - currently unused. ICU 2.6, Alan +// //------------------------------------------------------------------------- +// // Alternate Sun Rise/Set +// // See sci.astro FAQ +// // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html +// //------------------------------------------------------------------------- +// +// // Note: This method appears to produce inferior accuracy as +// // compared to getSunRiseSet(). +// +// /** +// * TODO Make this when the entire class is package-private. +// */ +// /*public*/ long getSunRiseSet3(boolean rise) { +// +// // Compute day number for 0.0 Jan 2000 epoch +// double d = (double)(time - EPOCH_2000_MS) / DAY_MS; +// +// // Now compute the Local Sidereal Time, LST: +// // +// double LST = 98.9818 + 0.985647352 * d + /*UT*15 + long*/ +// fLongitude*RAD_DEG; +// // +// // (east long. positive). Note that LST is here expressed in degrees, +// // where 15 degrees corresponds to one hour. Since LST really is an angle, +// // it's convenient to use one unit---degrees---throughout. +// +// // COMPUTING THE SUN'S POSITION +// // ---------------------------- +// // +// // To be able to compute the Sun's rise/set times, you need to be able to +// // compute the Sun's position at any time. First compute the "day +// // number" d as outlined above, for the desired moment. Next compute: +// // +// double oblecl = 23.4393 - 3.563E-7 * d; +// // +// double w = 282.9404 + 4.70935E-5 * d; +// double M = 356.0470 + 0.9856002585 * d; +// double e = 0.016709 - 1.151E-9 * d; +// // +// // This is the obliquity of the ecliptic, plus some of the elements of +// // the Sun's apparent orbit (i.e., really the Earth's orbit): w = +// // argument of perihelion, M = mean anomaly, e = eccentricity. +// // Semi-major axis is here assumed to be exactly 1.0 (while not strictly +// // true, this is still an accurate approximation). Next compute E, the +// // eccentric anomaly: +// // +// double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) ); +// // +// // where E and M are in degrees. This is it---no further iterations are +// // needed because we know e has a sufficiently small value. Next compute +// // the true anomaly, v, and the distance, r: +// // +// /* r * cos(v) = */ double A = cos(E*DEG_RAD) - e; +// /* r * ::sin(v) = */ double B = ::sqrt(1 - e*e) * ::sin(E*DEG_RAD); +// // +// // and +// // +// // r = sqrt( A*A + B*B ) +// double v = ::atan2( B, A )*RAD_DEG; +// // +// // The Sun's true longitude, slon, can now be computed: +// // +// double slon = v + w; +// // +// // Since the Sun is always at the ecliptic (or at least very very close to +// // it), we can use simplified formulae to convert slon (the Sun's ecliptic +// // longitude) to sRA and sDec (the Sun's RA and Dec): +// // +// // ::sin(slon) * cos(oblecl) +// // tan(sRA) = ------------------------- +// // cos(slon) +// // +// // ::sin(sDec) = ::sin(oblecl) * ::sin(slon) +// // +// // As was the case when computing az, the Azimuth, if possible use an +// // atan2() function to compute sRA. +// +// double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG; +// +// double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD); +// double sDec = ::asin(sin_sDec)*RAD_DEG; +// +// // COMPUTING RISE AND SET TIMES +// // ---------------------------- +// // +// // To compute when an object rises or sets, you must compute when it +// // passes the meridian and the HA of rise/set. Then the rise time is +// // the meridian time minus HA for rise/set, and the set time is the +// // meridian time plus the HA for rise/set. +// // +// // To find the meridian time, compute the Local Sidereal Time at 0h local +// // time (or 0h UT if you prefer to work in UT) as outlined above---name +// // that quantity LST0. The Meridian Time, MT, will now be: +// // +// // MT = RA - LST0 +// double MT = normalize(sRA - LST, 360); +// // +// // where "RA" is the object's Right Ascension (in degrees!). If negative, +// // add 360 deg to MT. If the object is the Sun, leave the time as it is, +// // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from +// // sidereal to solar time. Now, compute HA for rise/set, name that +// // quantity HA0: +// // +// // ::sin(h0) - ::sin(lat) * ::sin(Dec) +// // cos(HA0) = --------------------------------- +// // cos(lat) * cos(Dec) +// // +// // where h0 is the altitude selected to represent rise/set. For a purely +// // mathematical horizon, set h0 = 0 and simplify to: +// // +// // cos(HA0) = - tan(lat) * tan(Dec) +// // +// // If you want to account for refraction on the atmosphere, set h0 = -35/60 +// // degrees (-35 arc minutes), and if you want to compute the rise/set times +// // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes). +// // +// double h0 = -50/60 * DEG_RAD; +// +// double HA0 = ::acos( +// (sin(h0) - ::sin(fLatitude) * sin_sDec) / +// (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG; +// +// // When HA0 has been computed, leave it as it is for the Sun but multiply +// // by 365.2422/366.2422 for stellar objects, to convert from sidereal to +// // solar time. Finally compute: +// // +// // Rise time = MT - HA0 +// // Set time = MT + HA0 +// // +// // convert the times from degrees to hours by dividing by 15. +// // +// // If you'd like to check that your calculations are accurate or just +// // need a quick result, check the USNO's Sun or Moon Rise/Set Table, +// // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>. +// +// double result = MT + (rise ? -HA0 : HA0); // in degrees +// +// // Find UT midnight on this day +// long midnight = DAY_MS * (time / DAY_MS); +// +// return midnight + (long) (result * 3600000 / 15); +// } + +//------------------------------------------------------------------------- +// The Moon +//------------------------------------------------------------------------- + +#define moonL0 (318.351648 * CalendarAstronomer::PI/180 ) // Mean long. at epoch +#define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 ) // Mean long. of perigee +#define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 ) // Mean long. of node +#define moonI ( 5.145366 * CalendarAstronomer::PI/180 ) // Inclination of orbit +#define moonE ( 0.054900 ) // Eccentricity of orbit + +// These aren't used right now +#define moonA ( 3.84401e5 ) // semi-major axis (km) +#define moonT0 ( 0.5181 * CalendarAstronomer::PI/180 ) // Angular size at distance A +#define moonPi ( 0.9507 * CalendarAstronomer::PI/180 ) // Parallax at distance A + +/** + * The position of the moon at the time set on this + * object, in equatorial coordinates. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition() +{ + // + // See page 142 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + // + if (moonPositionSet == FALSE) { + // Calculate the solar longitude. Has the side effect of + // filling in "meanAnomalySun" as well. + getSunLongitude(); + + // + // Find the # of days since the epoch of our orbital parameters. + // TODO: Convert the time of day portion into ephemeris time + // + double day = getJulianDay() - JD_EPOCH; // Days since epoch + + // Calculate the mean longitude and anomaly of the moon, based on + // a circular orbit. Similar to the corresponding solar calculation. + double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0); + meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0); + + // + // Calculate the following corrections: + // Evection: the sun's gravity affects the moon's eccentricity + // Annual Eqn: variation in the effect due to earth-sun distance + // A3: correction factor (for ???) + // + double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude) + - meanAnomalyMoon); + double annual = 0.1858*PI/180 * ::sin(meanAnomalySun); + double a3 = 0.3700*PI/180 * ::sin(meanAnomalySun); + + meanAnomalyMoon += evection - annual - a3; + + // + // More correction factors: + // center equation of the center correction + // a4 yet another error correction (???) + // + // TODO: Skip the equation of the center correction and solve Kepler's eqn? + // + double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon); + double a4 = 0.2140*PI/180 * ::sin(2 * meanAnomalyMoon); + + // Now find the moon's corrected longitude + moonLongitude = meanLongitude + evection + center - annual + a4; + + // + // And finally, find the variation, caused by the fact that the sun's + // gravitational pull on the moon varies depending on which side of + // the earth the moon is on + // + double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude)); + + moonLongitude += variation; + + // + // What we've calculated so far is the moon's longitude in the plane + // of its own orbit. Now map to the ecliptic to get the latitude + // and longitude. First we need to find the longitude of the ascending + // node, the position on the ecliptic where it is crossed by the moon's + // orbit as it crosses from the southern to the northern hemisphere. + // + double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day); + + nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun); + + double y = ::sin(moonLongitude - nodeLongitude); + double x = cos(moonLongitude - nodeLongitude); + + moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude; + double moonEclipLat = ::asin(y * ::sin(moonI)); + + eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat); + moonPositionSet = TRUE; + } + return moonPosition; +} + +/** + * The "age" of the moon at the time specified in this object. + * This is really the angle between the + * current ecliptic longitudes of the sun and the moon, + * measured in radians. + * + * @see #getMoonPhase + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getMoonAge() { + // See page 147 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + // + // Force the moon's position to be calculated. We're going to use + // some the intermediate results cached during that calculation. + // + getMoonPosition(); + + return norm2PI(moonEclipLong - sunLongitude); +} + +/** + * Calculate the phase of the moon at the time set in this object. + * The returned phase is a <code>double</code> in the range + * <code>0 <= phase < 1</code>, interpreted as follows: + * <ul> + * <li>0.00: New moon + * <li>0.25: First quarter + * <li>0.50: Full moon + * <li>0.75: Last quarter + * </ul> + * + * @see #getMoonAge + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +double CalendarAstronomer::getMoonPhase() { + // See page 147 of "Practial Astronomy with your Calculator", + // by Peter Duffet-Smith, for details on the algorithm. + return 0.5 * (1 - cos(getMoonAge())); +} + +/** + * Constant representing a new moon. + * For use with {@link #getMoonTime getMoonTime} + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() { + return CalendarAstronomer::MoonAge(0); +} + +/** + * Constant representing the moon's first quarter. + * For use with {@link #getMoonTime getMoonTime} + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +/*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() { + return CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2); +}*/ + +/** + * Constant representing a full moon. + * For use with {@link #getMoonTime getMoonTime} + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() { + return CalendarAstronomer::MoonAge(CalendarAstronomer::PI); +} +/** + * Constant representing the moon's last quarter. + * For use with {@link #getMoonTime getMoonTime} + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ + +class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc { +public: + virtual ~MoonTimeAngleFunc(); + virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); } +}; + +MoonTimeAngleFunc::~MoonTimeAngleFunc() {} + +/*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() { + return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2); +}*/ + +/** + * Find the next or previous time at which the Moon's ecliptic + * longitude will have the desired value. + * <p> + * @param desired The desired longitude. + * @param next <tt>true</tt> if the next occurrance of the phase + * is desired, <tt>false</tt> for the previous occurrance. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +UDate CalendarAstronomer::getMoonTime(double desired, UBool next) +{ + MoonTimeAngleFunc func; + return timeOfAngle( func, + desired, + SYNODIC_MONTH, + MINUTE_MS, + next); +} + +/** + * Find the next or previous time at which the moon will be in the + * desired phase. + * <p> + * @param desired The desired phase of the moon. + * @param next <tt>true</tt> if the next occurrance of the phase + * is desired, <tt>false</tt> for the previous occurrance. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) { + return getMoonTime(desired.value, next); +} + +class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc { +public: + virtual ~MoonRiseSetCoordFunc(); + virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); } +}; + +MoonRiseSetCoordFunc::~MoonRiseSetCoordFunc() {} + +/** + * Returns the time (GMT) of sunrise or sunset on the local date to which + * this calendar is currently set. + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +UDate CalendarAstronomer::getMoonRiseSet(UBool rise) +{ + MoonRiseSetCoordFunc func; + return riseOrSet(func, + rise, + .533 * DEG_RAD, // Angular Diameter + 34 /60.0 * DEG_RAD, // Refraction correction + MINUTE_MS); // Desired accuracy +} + +//------------------------------------------------------------------------- +// Interpolation methods for finding the time at which a given event occurs +//------------------------------------------------------------------------- + +UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired, + double periodDays, double epsilon, UBool next) +{ + // Find the value of the function at the current time + double lastAngle = func.eval(*this); + + // Find out how far we are from the desired angle + double deltaAngle = norm2PI(desired - lastAngle) ; + + // Using the average period, estimate the next (or previous) time at + // which the desired angle occurs. + double deltaT = (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2; + + double lastDeltaT = deltaT; // Liu + UDate startTime = fTime; // Liu + + setTime(fTime + uprv_ceil(deltaT)); + + // Now iterate until we get the error below epsilon. Throughout + // this loop we use normPI to get values in the range -Pi to Pi, + // since we're using them as correction factors rather than absolute angles. + do { + // Evaluate the function at the time we've estimated + double angle = func.eval(*this); + + // Find the # of milliseconds per radian at this point on the curve + double factor = uprv_fabs(deltaT / normPI(angle-lastAngle)); + + // Correct the time estimate based on how far off the angle is + deltaT = normPI(desired - angle) * factor; + + // HACK: + // + // If abs(deltaT) begins to diverge we need to quit this loop. + // This only appears to happen when attempting to locate, for + // example, a new moon on the day of the new moon. E.g.: + // + // This result is correct: + // newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))= + // Sun Jul 22 10:57:41 CST 1990 + // + // But attempting to make the same call a day earlier causes deltaT + // to diverge: + // CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 -> + // 1.3649828540224032E9 + // newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))= + // Sun Jul 08 13:56:15 CST 1990 + // + // As a temporary solution, we catch this specific condition and + // adjust our start time by one eighth period days (either forward + // or backward) and try again. + // Liu 11/9/00 + if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) { + double delta = uprv_ceil (periodDays * DAY_MS / 8.0); + setTime(startTime + (next ? delta : -delta)); + return timeOfAngle(func, desired, periodDays, epsilon, next); + } + + lastDeltaT = deltaT; + lastAngle = angle; + + setTime(fTime + uprv_ceil(deltaT)); + } + while (uprv_fabs(deltaT) > epsilon); + + return fTime; +} + +UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise, + double diameter, double refraction, + double epsilon) +{ + Equatorial pos; + double tanL = ::tan(fLatitude); + double deltaT = 0; + int32_t count = 0; + + // + // Calculate the object's position at the current time, then use that + // position to calculate the time of rising or setting. The position + // will be different at that time, so iterate until the error is allowable. + // + U_DEBUG_ASTRO_MSG(("setup rise=%s, dia=%.3lf, ref=%.3lf, eps=%.3lf\n", + rise?"T":"F", diameter, refraction, epsilon)); + do { + // See "Practical Astronomy With Your Calculator, section 33. + func.eval(pos, *this); + double angle = ::acos(-tanL * ::tan(pos.declination)); + double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2; + + // Convert from LST to Universal Time. + UDate newTime = lstToUT( lst ); + + deltaT = newTime - fTime; + setTime(newTime); + U_DEBUG_ASTRO_MSG(("%d] dT=%.3lf, angle=%.3lf, lst=%.3lf, A=%.3lf/D=%.3lf\n", + count, deltaT, angle, lst, pos.ascension, pos.declination)); + } + while (++ count < 5 && uprv_fabs(deltaT) > epsilon); + + // Calculate the correction due to refraction and the object's angular diameter + double cosD = ::cos(pos.declination); + double psi = ::acos(sin(fLatitude) / cosD); + double x = diameter / 2 + refraction; + double y = ::asin(sin(x) / ::sin(psi)); + long delta = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS); + + return fTime + (rise ? -delta : delta); +} + /** + * Return the obliquity of the ecliptic (the angle between the ecliptic + * and the earth's equator) at the current time. This varies due to + * the precession of the earth's axis. + * + * @return the obliquity of the ecliptic relative to the equator, + * measured in radians. + */ +double CalendarAstronomer::eclipticObliquity() { + if (isINVALID(eclipObliquity)) { + const double epoch = 2451545.0; // 2000 AD, January 1.5 + + double T = (getJulianDay() - epoch) / 36525; + + eclipObliquity = 23.439292 + - 46.815/3600 * T + - 0.0006/3600 * T*T + + 0.00181/3600 * T*T*T; + + eclipObliquity *= DEG_RAD; + } + return eclipObliquity; +} + + +//------------------------------------------------------------------------- +// Private data +//------------------------------------------------------------------------- +void CalendarAstronomer::clearCache() { + const double INVALID = uprv_getNaN(); + + julianDay = INVALID; + julianCentury = INVALID; + sunLongitude = INVALID; + meanAnomalySun = INVALID; + moonLongitude = INVALID; + moonEclipLong = INVALID; + meanAnomalyMoon = INVALID; + eclipObliquity = INVALID; + siderealTime = INVALID; + siderealT0 = INVALID; + moonPositionSet = FALSE; +} + +//private static void out(String s) { +// System.out.println(s); +//} + +//private static String deg(double rad) { +// return Double.toString(rad * RAD_DEG); +//} + +//private static String hours(long ms) { +// return Double.toString((double)ms / HOUR_MS) + " hours"; +//} + +/** + * @internal + * @deprecated ICU 2.4. This class may be removed or modified. + */ +/*UDate CalendarAstronomer::local(UDate localMillis) { + // TODO - srl ? + TimeZone *tz = TimeZone::createDefault(); + int32_t rawOffset; + int32_t dstOffset; + UErrorCode status = U_ZERO_ERROR; + tz->getOffset(localMillis, TRUE, rawOffset, dstOffset, status); + delete tz; + return localMillis - rawOffset; +}*/ + +// Debugging functions +UnicodeString CalendarAstronomer::Ecliptic::toString() const +{ +#ifdef U_DEBUG_ASTRO + char tmp[800]; + sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG); + return UnicodeString(tmp, ""); +#else + return UnicodeString(); +#endif +} + +UnicodeString CalendarAstronomer::Equatorial::toString() const +{ +#ifdef U_DEBUG_ASTRO + char tmp[400]; + sprintf(tmp, "%f,%f", + (ascension*RAD_DEG), (declination*RAD_DEG)); + return UnicodeString(tmp, ""); +#else + return UnicodeString(); +#endif +} + +UnicodeString CalendarAstronomer::Horizon::toString() const +{ +#ifdef U_DEBUG_ASTRO + char tmp[800]; + sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG); + return UnicodeString(tmp, ""); +#else + return UnicodeString(); +#endif +} + + +// static private String radToHms(double angle) { +// int hrs = (int) (angle*RAD_HOUR); +// int min = (int)((angle*RAD_HOUR - hrs) * 60); +// int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600); + +// return Integer.toString(hrs) + "h" + min + "m" + sec + "s"; +// } + +// static private String radToDms(double angle) { +// int deg = (int) (angle*RAD_DEG); +// int min = (int)((angle*RAD_DEG - deg) * 60); +// int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600); + +// return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\""; +// } + +// =============== Calendar Cache ================ + +void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) { + ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup); + if(cache == NULL) { + status = U_MEMORY_ALLOCATION_ERROR; + } else { + *cache = new CalendarCache(32, status); + if(U_FAILURE(status)) { + delete *cache; + *cache = NULL; + } + } +} + +int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) { + int32_t res; + + if(U_FAILURE(status)) { + return 0; + } + umtx_lock(&ccLock); + + if(*cache == NULL) { + createCache(cache, status); + if(U_FAILURE(status)) { + umtx_unlock(&ccLock); + return 0; + } + } + + res = uhash_igeti((*cache)->fTable, key); + U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res)); + + umtx_unlock(&ccLock); + return res; +} + +void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) { + if(U_FAILURE(status)) { + return; + } + umtx_lock(&ccLock); + + if(*cache == NULL) { + createCache(cache, status); + if(U_FAILURE(status)) { + umtx_unlock(&ccLock); + return; + } + } + + uhash_iputi((*cache)->fTable, key, value, &status); + U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value)); + + umtx_unlock(&ccLock); +} + +CalendarCache::CalendarCache(int32_t size, UErrorCode &status) { + fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status); + U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable)); +} + +CalendarCache::~CalendarCache() { + if(fTable != NULL) { + U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable)); + uhash_close(fTable); + } +} + +U_NAMESPACE_END + +#endif // !UCONFIG_NO_FORMATTING |