Common Block Variables

The remaining common block variables in spha.h, to which almost all subroutines have access, are listed here:

NAV, ALPHA, BETA, ETA2:

These are all described in Sec. 5.1.1, and set values for the AV routines.

NGR, XGRMIN, XGRMAX, YGRMIN, YGRMAX, ZGRMIN, ZGRMAX,

XGRLIM, YGRLIM, ZGRLIM: These are all described in Sec. 5.1.1, and set values for the gravity routines.

NRELAX, TRELAX, TRELOFF:

These are all described in Sec. 5.1.1, and set values for the relaxation routines.

OMEGA2:

This is $\Omega^2$, the square of the orbital velocity.

NLEFT:

This is the number of particles in the primary. Loops which distinguish between the stars in a binary loop from $1\le i \le {\tt NLEFT}$, and ${\tt NLEFT}+1\le i \le{\tt N}$.

SEP0, QDAR, AMNS, RNS, RP, VPEAK:

These are all described in Sec. 5.1.1, and set parameters for the two stars.

N, NNOPT, GAM, HMIN, HMAX:

These are all described in Sec. 5.1.1, and set some global parameters.

NOUT, NIT:

These are respectively, the current count of output files written by subroutine DUOUT, and the number of iterations completed.

DT, T:

These are the current timestep and the current time in code units.

VXS, VYS, VZS, XM2, YM2, ZM2:

These are the velocities and positions of each particle, corrected to subtract off shifts in the system center-of-mass and the leapfrog timestep, used in the output routines.

TF, DTOUT:

These are all described in Sec. 5.1.1, representing the time at which the run ends, and the time interval between writing output files.

WTAB, DWTAB, CTAB:

The tabulated kernel function and its derivative, and a scalar representing the stepsize within the tabulated vector.

X, Y, Z, VX, VY, VZ, AM, HP, A, RHO, POR2, GRPOT:

Vectors containing, for each particle, the position, velocity, mass, smoothing length, entropic variable, density, the quantity $P/\rho^2$, and the gravitational potential.

VXDOT, VYDOT, VZDOT, ADOT:

The acceleration and rate of change of the entropic variable, for every particle.

GX, GY, GZ:

The gravitational force for every particle.

UX, UY, UZ:

Alternate velocity used when radiation reaction is included, see Sec. 3.6 and Eq. 3-31 for more info.

XIJ, YIJ, ZIJ:

The vector difference in position between a particle and its neighbors, calculated once to save time, at the cost of memory usage.

NNI:

An array of each particle's neighbors.

NN:

A vector containing the number of neighbors each particle has.

MYRANK:

The rank of each processor, returned by MPI_COMM_RANK.

N_LOWER, N_UPPER:

The range of particles covered by each processor for parallel distributed computational loops.

KSTART, KOFFSET:

Parameters used to section the 3-d gravity grids for parallel FFTs.

Q3XX, Q3XY, Q3XZ, Q3YY, Q3YZ, Q3ZZ:

Third time-derivative of the quadrupole tensor, used for calculating radiation reaction.

Q2XX, Q2XY, Q2XZ, Q2YY, Q2YZ, Q2ZZ:

Second time-derivative of the quadrupole tensor, used for calculating gravitational waveforms.

NGRAVRAD, SOL:

Parameter used to determine whether radiation reaction will be used, and the speed of light in code units, see Sec. 5.1.1.

INITGR:

Integer used to delay turning on radiation reaction for two iterations when dynamical run starts, since initial values are often inaccurate.

FREACX, FREACY, FREACZ:

Radiation reaction force on each particle.

GXX, GXY, GXZ, GYY, GYZ, GZZ:

Second derivatives of the gravitational potential, used in calculating the radiation reaction force.

DXPNR, DYPNR, DZPNR:

Derivatives of one of the radiation reaction potentials.