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\noindent
\centerline { NBODY6 ROUTINES}
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\settabs\+&XXXXXXXx&xXXXXXXXXXXXXX&XXXXXXX  \cr
\+&Routine &Called by &Description  \cr
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\medskip
\+&ADJUST &NBODY6  &Parameter adjustment \& energy check. \cr
\+&ASSESS &KSINT  &Assessment of hierarchical stability. \cr
\+&BINDAT &OUTPUT &Binary data bank on unit 9 (option 8 $>=$ 3). \cr
\+&BINEV &CHAOS \& MDOT &Stages of binary evolution (also COAL). \cr
\+&BINOUT &OUTPUT &Binary analysis \& output (\#8 $>$ 0). \cr
\+&BINPOP &DATA &Initial binary distribution (\#8). \cr
\+&BLOCK &        &Block data initialization of local labelled COMMON. \cr
\+&BODIES &OUTPUT &Output of single particles \& binaries (\#9 \& \#6). \cr
\+&BRAKE  &UNPERT &Magnetic braking and gravitational radiation (\#28). \cr
\+&BRAKE2 &MDOT &Gravitational radiation of hierarchical binary. \cr
\+&BSETID &MDOT \& ROCHE &Tidal synchronization for circular orbits (\#34). \cr
\+&CHAOS0 &CHAOS \& CHRECT &Initial chaos boundary (\#27; also HIGROW). \cr
\+&CHAOS  &KSTIDE &Chaotic tidal interactions (\#27). \cr
\+&CHECK  &ADJUST &Error check \& restart (\#2 \& \#17). \cr
\+&CHECKL &REGINT &Addition of neighbours during regular step (\#18). \cr
\+&CHRECT &KSINT \& MDOT &Rectification of chaotic orbits (\#27; also DECIDE). \cr
\+&CLINT &INTGRT  &Integration of interstellar cloud (\#13). \cr
\+&CLOUD0 &START &Initialization of cloud parameters (\#13). \cr
\+&CLOUD  &CLOUD0 \& NBINT &Generation of interstellar cloud (\#13). \cr
\+&CMBODY &KSINT \& TRIPLE &Formation of c.m. body by collision (also CHAIN). \cr
\+&CMCORR &ADJUST &Correction of c.m. coordinates \& velocities (\#31). \cr
\+&CMFIRR &NBINT &Irregular force on c.m. particle. \cr
\+&CMFREG &REGINT &Regular \& irregular force on c.m. particle. \cr
\+&COAL   &EXPEL \& EXPEL2 &Coalescence of Roche or CE binary (\#34). \cr
\+&COMENV &ROCHE \& EXPEL &Common envelope evolution (\#34 \& \#19). \cr
\+&CORE   &ADJUST \& OUTPUT &Density centre \& core radius. \cr
\+&CORERD &DGCORE \& SYNCH &Core radius of giant (\#19; also SPIRAL). \cr
\+&CPUTIM &ADJUST \& INTGRT &Elapsed CPU time in minutes (initialized in NBODY6). \cr
\+&DATA   &START  &Generation of initial conditions. \cr
\+&DECIDE &IMPACT &Hierarchical stability decisions. \cr
\+&DEFINE &INPUT &Definition of input parameters, options \& counters. \cr
\+&DEFORM &IMPACT \& ROCHE &Deformation of elliptic orbits (also SYNCH). \cr
\+&DEGEN  &MDOT \& ROCHE &Degenerate binary diagnostics (\#19; also CMBODY). \cr
\+&DELAY  &IMPACT \& INTGRT &Delay of multiple reqularization \& merger (\#15). \cr
\+&DGCORE &COMENV &Collision or coalescence of two degenerate cores (\#34). \cr
\+&DTCHCK &CMBODY \& COAL &Maximum commensurate step for activating ghosts. \cr
\+&ECCMOD &KSINT &Eccentricity modulation of hierarchical binary (\#27). \cr
\+&ECIRC  &DECIDE &Eccentricity for a given circularization time (\#27). \cr
\+&EDOT   &DECIDE &Eccentricity derivative due to dominant perturber (\#27). \cr
\+&EFAC2 &TIDES  &Tidal capture efficiency factor for second harmonic. \cr
\+&EFAC3 &TIDES  &Tidal capture efficiency factor for third harmonic. \cr
\+&ENERGY &ADJUST \& SCALE &Total energy (including binaries \& tidal field). \cr
\+&ESCAPE &ADJUST &Removal of escaping particles (\#23). \cr
\+&EVENTS &OUTPUT &Output of mass loss \& tidal capture events (\#19 \& 27). \cr
\+&EVOLVE &INTGRT \& KSINT &Diagnostic output of interacting binaries (\#4; unused). \cr
\+&EXPAND &HCORR  &Expansion or contraction of KS orbit (\#19). \cr
\+&EXPEL  &CMBODY \& SPIRAL &Preparation for common envelope stage (\#19). \cr
\+&FCLOSE &CMBODY \& RESET &Force \& first derivative of close bodies (START3 \& 4). \cr
\+&FCLOUD &REGINT \& FPOLY1 &Force \& derivative from interstellar clouds (\#13). \cr
\+&FCORR  &MDOT  &Global corrections for mass loss from evolving stars. \cr
\+&FDISK  &XTRNLF \& GCINT &Tidal force due to Miyamoto disk (\#14 = 3). \cr
\+&FHALO  &XTRNLF \& GCINT &Tidal force due to logarithmic halo (\#14 = 3). \cr
\+&FICORR &MDOT  &Local corrections due to mass loss. \cr
\+&FINDJ &BINDAT \& HRPLOT &Find merger and ghost index (also MDOT). \cr
\+&FINDM &NEWTEV &Find ghost mass. \cr
\+&FLYBY  &KSINT &Termination check of perturbed KS orbit. \cr
\+&FNUC  &XTRNLF \& GCINT &Tidal force due to point-mass (\#14 = 3). \cr
\+&FPCORR &REGINT &Force polynomial derivative corrections (\#38). \cr
\+&FPERT &SEARCH \& IMPACT &Perturbing force on dominant components. \cr
\+&FPOLY1 &START \& KSINIT &Total force \& first derivative (also START3 \& 4). \cr
\+&FPOLY2 &START \& KSINIT &Second \& third force derivatives (also START3 \& 4). \cr
\+&FREEZE &KSINT &Partial reflection of KS orbit (\#25; suppressed). \cr
\+&GCINIT &XTRNL0 &Initialization of guiding centre orbit (\#14 = 3). \cr
\+&GCINT  &INTGRT &Integration of guiding centre (\#14 = 3). \cr
\+&GIANT  &CHAOS \& SYNCH &Structure constants of giant star (\#19; also TCIRC). \cr
\+&GIANT3 &HIGROW \& QTIDES &Structure constants of giant star (\#19 \& 27). \cr
\+&GNTAGE &CMBODY &Age of giant star. \cr
\+&GRRAD  &MDOT \& ROCHE &Gravitational radiation for close binary (\#19). \cr
\+&HCORR  &MDOT  &Mass loss correction of KS orbit (\#19). \cr
\+&HIARCH &MERGE \& RESET &Diagnostics of hierarchical systems (\#18; also ESCAPE). \cr
\+&HICIRC &ECCMOD \& HIGROW &Eccentricity for given $T_{circ}$ in hierarchy (\#27). \cr
\+&HIDAT  &OUTPUT &Hierarchical data bank on unit \#87 (\#8 $>$ 3). \cr
\+&HIGROW &ECCMOD &Induced change of hierarchical binary (\#27). \cr
\+&HIMAX  &HIDAT  &Maximum eccentricity of hierarchy. \cr
\+&HIMOD  &HIGROW &Modification of hierarchical binary (\#27). \cr
\+&HIPOP  &START  &Primordial hierarchical triples (\#18 = 2). \cr
\+&HIRECT &HIGROW \& BRAKE2 &Rectification of hierarchical binary (\#27). \cr
\+&HISTAB &UNPERT &Hierarchical stability criterion (MA99). \cr
\+&HIVEL  &INTGRT &High-velocity particle search (\# 37 $>$ 0). \cr
\+&HMDOT  &MDOT  &Mass loss from inner hierarchical binary (\#19). \cr
\+&HMDOT2 &MDOT  &Mass loss from outer hierarchical binary (\#19). \cr
\+&HOTSYS  &START  &Hot initial system (\#29; suppressed). \cr
\+&HRDIAG  &INSTAR \& MDOT &H-R parameters for stellar evolution (\#19 \& 27). \cr
\+&HRPLOT  &OUTPUT &HR diagram of evolving stars (\#12). \cr
\+&HUT   &SPIRAL &Evolution equations for eccentricity and spin (\#27). \cr
\+&HUT2  &SYNCH &Spin evolution of circular binary (\#27). \cr
\+&IBLOCK  &START  &Initialization of hierarchical block-steps (40 levels). \cr
\+&IMF  &DATA  &Initial mass function (\#20 = 1; iteration method). \cr
\+&IMF2 &DATA  &Initial mass function (\#20 $>$ 1; binaries \& singles). \cr
\+&IMFBD &IMF2 &IMF with brown dwarfs (\#20 = 6; Pavel Kroupa version). \cr
\+&IMPACT &KSINT \& UNPERT &Search for multiple encounters or merger (\#15). \cr
\+&INDUCE &IMPACT \& KSTIDE &Induced eccentricity of hierarchical binary (\#27). \cr
\+&INEXT  &INTGRT &Determination of next particles. \cr
\+&INPUT  &START  &Main input. \cr
\+&INSERT &SUBINT &Insertion of particle index in KS time-step list. \cr
\+&INSTAR &START &Initialization of stellar evolution parameters (\#19). \cr
\+&INTGRT &NBODY6   &Decision-making \& control of integration paths. \cr
\+&INTIDE &START  &Input \& scaling for tidal capture (\#27; suppressed). \cr
\+&JACOBI &OUTPUT &Current escaper number (with or without tidal field). \cr
\+&KEPLER &NBINT &Step reduction of binary c.m. \& close perturber (\#36). \cr
\+&KICK   &KSAPO \& FCORR &Velocity kick for neutron stars (\#19). \cr
\+&KICK2  &ROCHE &Velocity kick for Roche NS \& BH stars (\#34). \cr
\+&KSAPO  &UNPERT &Transformation of KS variables by PI/2 or at random. \cr
\+&KSCORR &KSINT &Stumpff corrector for KS regularization. \cr
\+&KSIN2  &MERGE2 \& RESET2 &Initialization of hierarchical KS. \cr
\+&KSINIT &KSREG &Initialization of KS regularization. \cr
\+&KSINT  &INTGRT &Regularized two-body integration. \cr
\+&KSLIST &KSINT \& RESET &Selection of KS perturbers (also KSINIT \& KSTIDE). \cr
\+&KSMOD &KSINT &KS motion modified by slow-down (\#26). \cr
\+&KSPERI  &KSINT \& KSTIDE &KS variables at pericentre. \cr
\+&KSPERT &KSINT  &Perturbation on KS pair. \cr
\+&KSPOLY &KSINIT \& KSINT &New KS polynomials (also KSMOD \& RESET). \cr
\+&KSPRED &KSINT &Prediction for KS regularization. \cr
\+&KSRECT &KSTERM &Rectification of KS variables to correct energy. \cr
\+&KSREG &NBODY6 \& MERGE  &Preparation of new KS regularization (also RESET). \cr
\+&KSRES  &MERGE \& XTPERT &Interpolation \& coordinate transformation of KS pair. \cr
\+&KSRES2 &INTGRT \& CMFIRR &Coordinates \& velocities of KS pair. \cr
\+&KSTERM &NBODY6 \& MERGE &Termination of KS regularization (RESET \& IMPACT). \cr
\+&KSTIDE &KSINT  &Tidal interaction of KS pair (\#27). \cr
\+&LAGR   &ADJUST \& OUTPUT &Lagrangian radii \& half-mass radius (\#7). \cr
\+&LAGR2  &OUTPUT &Lagrangian \& half-mass radi of two mass groups (\#7 = 6). \cr
\+&LEVELS &OUTPUT &Diagnostic output of block-steps (\#33). \cr
\+&MAGBRK &MDOT \& ROCHE &Spin change due to magnetic braking (\#19, \#34). \cr
\+&MATRIX &KSINIT \& KSPOLY &Levi-Civita matrix (also KSCORR, KSRES2 \& RESOLV). \cr
\+&MDOT   &INTGRT &Mass loss from evolving stars (\#19 $>=$ 3). \cr
\+&MERGE  &NBODY6   &Merging of hierarchical triple or quadrupole. \cr
\+&MERGE2 &MERGE  &Merging of double hierarchy. \cr
\+&MIX  &CMBODY &Evolution parameters for mixed star (\#19). \cr
\+&MLOSS  &INTGRT &Mass loss from evolving stars (old version; \#19 = 1). \cr
\+&MLWIND &MDOT &Reimers mass loss from stellar wind (\#19 $>=$ 3). \cr
\+&MODIFY &NBODY6 &Modified input parameters at restart. \cr
\+&MRENV  &HRDIAG &Mass and radius of convective envelope (\#19). \cr
\+&MTRACE &MDOT &Orbit diagnostics for mass loss (suppressed). \cr
\+&MYDUMP &ADJUST \& INTGRT &COMMON save or restart (also NBODY6; \#1 \& \#2). \cr
\+&NBINT  &INTGRT &Irregular integration and corrector. \cr
\+&NBLIST &START &Initialization of neighbour list (also START3 \& 4). \cr
\+&NBODY6  &        &Master control flow. \cr
\+&NBPOT &MERGE \& RESET &Potential energy of subsystem (also TRIPLE \& QUAD). \cr
\+&NBREM &MERGE &Ghost removal from neighbour lists (also START3 \& 4). \cr
\+&NBREST &RESET &Restoring ghosts in neighbour lists (also START3 \& 4). \cr
\+&NBSORT &INTGRT &Neighbour list sorting. \cr
\+&NBTIDE &NBINT  &Tidal two-body interaction (\#27 $<$ 0; suppressed). \cr
\+&NEWTEV &MERGE2 &Next look-up time for hierarchy (\#19 $>=$ 3). \cr
\+&NSTAB  &IMPACT &Three-body stability criterion (also ASSESS \& RESET2). \cr
\+&NTINT  &INTGRT &Integration of single stars in tidal field (\#23). \cr
\+&OFFSET &ADJUST &Offset of global times (\#35). \cr
\+&ORBIT &NBINT &Close encounter search for small eccentricity. \cr
\+&OUTPUT &ADJUST \& INTGRT   &Main output \& optional data save. \cr
\+&PERI &KSINT &Pericentre of two-body motion (also TRIPLE \& QUAD). \cr
\+&PERMIT &IMPACT &Decision-making for new triple, quad or chain. \cr
\+&PFAC &HIMAX  &Precession factor for hierarchy. \cr
\+&POTI &EXPEL \& MTRACE &Potential of one particle from explicit sum. \cr
\+&PROTO &BINPOP &Pre-main sequence binary evolution (Pavel Kroupa). \cr
\+&QTIDES &HIGROW &Quadrupole and tidal terms for hierarchical binary (\#27). \cr
\+&RAN2  &DATA \& BINPOP &Portable random number generator (also CLOUD). \cr
\+&REFLCT &REGINT &Boundary reflection (\#29; suppressed). \cr
\+&REGINT &INTGRT &Regular integration and corrector. \cr
\+&REMOVE &KSTERM \& ESCAPE &Removal of particle or KS pair from COMMON tables. \cr
\+&RENAME &KSREG &Renaming of COMMON tables for new KS pair. \cr
\+&RESET  &NBODY6 &Termination of hierarchical merger. \cr
\+&RESET2 &RESET &Termination of double hierarchy. \cr
\+&RESOLV &ENERGY \& XVPRED &Coordinates \& velocities of KS pair (also KSTERM). \cr
\+&RKINT  &HIMOD &Runge-Kutta integrator for tidal interactions (\#27). \cr
\+&RL  &ROCHE \& BRAKE2 &Analytical Roche radius relation (\#34). \cr
\+&ROCHE &MDOT &Treatment of Roche-lobe overflow (\#34). \cr
\+&RPMAX &KSINT &Maximum periastron factor for GR capture (\#27). \cr
\+&RPMAX2 &KSINT &Maximum periastron factor for capture (\#27). \cr
\+&RPMIN  &KSINT &Minimum distance for given GR energy change (\#27). \cr
\+&SCALE  &START &Scaling to new units. \cr
\+&SEARCH &NBINT &Close encounter search for KS regularization. \cr
\+&SETUP  &DATA &Initial coordinates \& velocities (\#22 = 0; Plummer). \cr
\+&SETUP2 &DATA &Initial conditions in astrophysical units (\#22 = -1). \cr
\+&SHRINK &INTGRT &Shrinking of regular steps in high-velocity encounters. \cr
\+&SORT1  &LAGR \& IMF2 &Sequential sorting of array (Numerical Recipes). \cr
\+&SPIRAL &CHAOS \& KSINT &Tidal circularization of binary (\#27; also SYNCH). \cr
\+&STABILTY &IMPACT \& HISTAB &Three-body stability criterion (MA 1999). \cr
\+&STAR   &INSTAR \& MDOT &Stellar luminosity \& evolution time (also CMBODY). \cr
\+&START  &NBODY6  &Initial setup \& force polynomials. \cr
\+&STEPK  &STEPS \& NBINT &Selection of block-steps (also in multiple regularizations). \cr
\+&STEPS  &FPOLY2 &Initialization of time-steps \& differences. \cr
\+&STUMPF &KSINT \& KSMOD &Modified Stumpff functions (also KSTERM). \cr
\+&SUBINT &INTGRT &Subsystem decision-making (KS, TRIPLE, QUAD, CHAIN). \cr
\+&SWAP  &START &Randomized particle swapping (GPU only). \cr
\+&SWEEP &ADJUST &Enforced KS reg of wide binaries (\#8 $>$ 0). \cr
\+&SYNCH &MDOT &Spin synchronization of circularized orbit (\#19). \cr
\+&TAIL0 &ESCAPE &Initialization of tidal tail stars (\#14, \#23). \cr
\+&TCIRC  &BINPOP &Pre-main sequence circularization. \cr
\+&TIDES  &KSTIDE \& TRIPLE  &Tidal energy loss of interacting stars (also QUAD). \cr
\+&TIDES2 &CHAOS &Tidal energy dissipation (\#27). \cr
\+&TIDES3 &KSTIDE &GR tidal energy loss (\#27). \cr
\+&TOUCH &KSINT \& UNPERT &Collision detector for KS pairs (\#27 = -1). \cr
\+&TPERT &KSMOD \& UNPERT &Perturbation time-scale. \cr
\+&TRDOT &MDOT \& ROCHE &Time-scale for radial expansion (\#19; SYNCH). \cr
\+&TRDOT2 &NEWTEV \& ROCHE &Time-scale for evolution changes (\#19). \cr
\+&TRFLOW &KSTIDE \& MDOT &Time until Roche overflow (\#34; ROCHE \& SYNCH). \cr
\+&TSTAB &IMPACT &Hierarchical stability time estimate. \cr
\+&TSTEP &NBINT \& STEPS  &Standard time-step expression. \cr
\+&UNITS  &START  &Initialization of units \& scaling factors. \cr
\+&UNPERT &KSINT &Unperturbed two-body motion (KS regularization). \cr
\+&UPDATE &KSTERM &Modification of COMMON tables after KS termination. \cr
\+&VERIFY &INPUT \& MODIFY  &Validation of main input and restart parameters. \cr
\+&XTRNL0 &START &Initialization of external force (\#14 = 1,2,3). \cr
\+&XTRNLD &FPOLY1 \& FPOLY2 &External force and higher derivatives on single particle. \cr
\+&XTRNLF &NBINT &External force \& first derivative on single particle. \cr
\+&XTRNLP &KSINT \& KSPOLY &External perturbation on KS pair. \cr
\+&XTRNLT &NTINT &Galactic force and first derivative (\#14). \cr
\+&XTRNLV &ENERGY \& NBPOT &External potential (also ESCAPE \& BODIES). \cr
\+&XVPRED &ADJUST \& MERGE &Prediction of coordinates \& velocities (also KSINIT). \cr
\+&ZARE  &IMPACT &Zare exchange stability criterion for hierarchies. \cr
\+&ZCNSTS &INSTAR \& NBODY6 &Initialization of metallicity parameters for ZFUNCS. \cr
\+&ZDATA &ZCNSTS &Metallicity block data for ZCNSTS. \cr
\+&ZERO &START &Initialization of global scalars. \cr
\+&ZFUNCS &STAR \& HRDIAG &Fitting functions for stellar evolution. \cr
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\vfill\eject
\centerline {Three-body regularization}
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\+&DERQP3 &DIFSY3 &Derivatives for AZ regularization. \cr
\+&DIFSY3 &TRIPLE &Bulirsch-Stoer integrator for AZ. \cr
\+&EREL3  &DERQP3 \& TRIPLE &Dominant two-body energy in triple system. \cr
\+&EXTEND &SUBSYS \& INTGRT &Size of unperturbed triple or quad. \cr
\+&QPMOD3 &TRIPLE &Modification of AZ variables for tidal dissipation. \cr
\+&STABL3 &QPMOD3 \& TRIPLE &Stability test of triple system. \cr
\+&STABLZ &STABL3 &Zare stability criterion for exchange. \cr
\+&START3 &TRIPLE &Initialization \& restart of triple configuration. \cr
\+&SUBSYS &START3 \& START4 &Initialization of subsystem (TRIPLE, QUAD \& CHAIN). \cr
\+&TPERI  &DERQP3 \& DERQP4 &Pericentre time for KS motion (also DERQP \& KSINIT). \cr
\+&TRANS3 &TRIPLE &Transformation of physical \& KS variables for AZ. \cr
\+&TRIPLE &NBODY6 \& INTGRT &Main routine for triple regularization. \cr
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\centerline {Four-body regularization}
\bigskip
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\medskip
\+&DERQP4 &DIFSY4 &Derivatives for four-body chain regularization. \cr
\+&DIFSY4 &QUAD   &Bulirsch-Stoer integrator for chain regularization. \cr
\+&ENDREG &QUAD \& RCHAIN &Transformation to physical variables. \cr
\+&EREL4  &DERQP4 \& QUAD &Dominant two-body energy in four-body system. \cr
\+&ICHAIN &STATUS &Determination of regularized chain. \cr
\+&NEWREG &QUAD \& RCHAIN &Initialization of four-body regularization. \cr
\+&NEWSYS &QUAD &Total energy of four-body configuration. \cr
\+&QPMOD4 &QUAD &Modification of quad variables for tidal dissipation. \cr
\+&QUAD   &NBODY6 \& INTGRT &Main routine for four-body regularization. \cr
\+&RCHAIN &QUAD &Decision-making for quad regularization. \cr
\+&RSORT  &RCHAIN \& STATUS &Sorting of four-body distances. \cr
\+&STABL4 &QPMOD4 &Stability test of four-body system. \cr
\+&START4 &QUAD &Initialization \& restart of four-body configuration. \cr
\+&STATUS &QUAD \& NEWREG &Sorting of square distances \& closest pair indices. \cr
\+&TRANS4 &EREL4  &Transformation to physical momenta. \cr
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\bye