File indexing completed on 2024-04-14 03:43:17

 /*
     SPDX-FileCopyrightText: 2008 Akarsh Simha <akarsh.simha@kdemail.net>
     SPDX-FileCopyrightText: 2018 Valentin Boettcher <valentin@boettcher.cf>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "approachsolver.h"
 #include <kstars_debug.h>
 
 ApproachSolver::ApproachSolver(QObject *parent) : QObject(parent)
 {
     m_geoPlace = KStarsData::Instance()->geo();
     m_Earth = KSPlanet(i18n("Earth"), QString(), QColor("white"), 12756.28 /*diameter in km*/);
 }
 
 void ApproachSolver::setGeoLocation(GeoLocation *geo)
 {
     if (geo != nullptr)
         m_geoPlace = geo;
     else
         m_geoPlace = KStarsData::Instance()->geo();
 }
 
 // FIXME: We need a better algo for finding approaches!
 QMap<long double, dms> ApproachSolver::findClosestApproach(long double startJD,
         long double stopJD, std::function<void (long double, dms)> const &callback)
 {
     QMap<long double, dms> Separations;
     QPair<long double, dms> extremum;
     dms Dist;
     dms prevDist;
 
     double step, step0;
     int Sign, prevSign;
 
     //  qCDebug(KSTARS) << "Entered KSConjunct::findClosestApproach() with startJD = " << (double)startJD;
     //  qCDebug(KSTARS) << "Initial Positional Information: \n";
     //  qCDebug(KSTARS) << m_object1->name() << ": RA = " << m_object1->ra() -> toHMSString() << "; Dec = " << m_object1->dec() -> toDMSString() << "\n";
     //  qCDebug(KSTARS) << m_object2->name() << ": RA = " << m_object2->ra() -> toHMSString() << "; Dec = " << m_object2->dec() -> toDMSString() << "\n";
     prevSign = 0;
 
     step0 = findInitialStep(startJD, stopJD);
     step = step0;
     //  qCDebug(KSTARS) << "Initial Separation between " << m_object1->name() << " and " << m_object2->name() << " = " << (prevDist.toDMSString());
 
     long double jd = startJD;
     prevDist       = updateAndFindDistance(jd);
     jd += step;
     while (jd <= stopJD)
     {
         int progress = int(100.0 * (jd - startJD) / (stopJD - startJD));
         emit solverMadeProgress(progress);
 
         Dist = updateAndFindDistance(jd);
         Sign = sgn(Dist - prevDist);
         //  qCDebug(KSTARS) << "Dist = " << Dist.toDMSString() << "; prevDist = " << prevDist.toDMSString() << "; Difference = " << (Dist.Degrees() - prevDist.Degrees()) << "; Step = " << step;
 
         //How close are we to a conjunction, and how fast are we approaching one?
         double factor = fabs((Dist.Degrees() - prevDist.Degrees()) / Dist.Degrees());
         if (factor > 10.0) //let's go faster!
         {
             step = step0 * factor / 10.0;
         }
         else //slow down, we're getting close!
         {
             step = step0;
         }
 
         if (Sign != prevSign && prevSign == -1) //all right, we may have just passed a conjunction
         {
             if (step > step0) //mini-loop to back up and make sure we're close enough
             {
                 //            qCDebug(KSTARS) << "Entering slow loop: ";
                 jd -= step;
                 step = step0;
                 Sign = prevSign;
                 while (jd <= stopJD)
                 {
                     Dist = updateAndFindDistance(jd);
                     Sign = sgn(Dist - prevDist);
                     //  qCDebug(KSTARS) << "Dist=" << Dist.toDMSString() << "; prevDist=" << prevDist.toDMSString() << "; Diff=" << (Dist.Degrees() - prevDist.Degrees()) << "djd=" << (int)(jd - startJD);
                     if (Sign != prevSign)
                         break;
 
                     prevDist = Dist;
                     prevSign = Sign;
                     jd += step;
                 }
             }
 
             //  qCDebug(KSTARS) << "Sign = " << Sign << " and " << "prevSign = " << prevSign << ": Entering findPrecise()\n";
             if (findPrecise(&extremum, jd, step, Sign))
             {
                 if (extremum.second.radians() < getMaxSeparation())
                 {
                     Separations.insert(extremum.first, extremum.second);
 
                     if(callback)
                         callback(extremum.first, extremum.second);
                 }
             }
         }
 
         prevDist = Dist;
         prevSign = Sign;
         jd += step;
     }
 
     return Separations;
 }
 
 bool ApproachSolver::findPrecise(QPair<long double, dms> *out, long double jd,
                                  double step, int prevSign)
 {
     dms prevDist;
     int Sign;
     dms Dist;
 
     if (out == nullptr)
     {
         qCDebug(KSTARS) << "ERROR: Argument out to KSConjunct::findPrecise(...) was nullptr!";
         return false;
     }
 
     prevDist = updateAndFindDistance(jd);
 
     step     = -step / 2.0;
     prevSign = -prevSign;
 
     while (true)
     {
         jd += step;
         Dist = updateAndFindDistance(jd);
         //    qCDebug(KSTARS) << "Dist=" << Dist.toDMSString() << "; prevDist=" << prevDist.toDMSString() << "; Diff=" << (Dist.Degrees() - prevDist.Degrees()) << "step=" << step;
 
         if (fabs(step) < 1.0 / (24.0 * 60.0))
         {
             out->first  = jd - step / 2.0;
             out->second = updateAndFindDistance(jd - step / 2.0);
             if (out->second.radians() < updateAndFindDistance(jd - 5.0).radians())
                 return true;
             else
                 return false;
         }
         Sign = sgn(Dist - prevDist);
         if (Sign != prevSign)
         {
             step = -step / 2.0;
             Sign = -Sign;
         }
         prevSign = Sign;
         prevDist = Dist;
     }
 }
 
 dms ApproachSolver::findSkyPointDistance(SkyPoint * obj1, SkyPoint * obj2)
 {
     dms dist;
     dist.setRadians(obj1->angularDistanceTo(obj2).radians());
     return dist;
 }
 
 int ApproachSolver::sgn(dms a)
 {
     // Auxiliary function used by the KSConjunct::findClosestApproach(...)
     // method and the KSConjunct::findPrecise(...) method
 
     return ((a.radians() > 0) ? 1 : ((a.radians() < 0) ? -1 : 0));
 }