Using a Single-star Configuration in a Binary: pos.sph

Since relaxation is not an option for irrotational or hyperbolic binaries, we require the use of a relaxed single-star configuration. These are optional as inputs for corotating binaries as well. These configurations are passed as ASCII files to the input routines from a file named pos.sph, and from a file named pos2.sph if the components of the binary are different. To create these files, take a restart file of either form mentioned in the previous section, and run the utility ``b2pos'' on it, producing a file named ``pos.sph'' (and ``b2pos2'' if necessary, it is the same executable, but produces a file named ``pos2.sph''). The first line of the file contains the parameters N, NNOPT, HMIN, HMAX, GAM, and TRELAX from the previous run. Following that is a list, one line per particle, containing the position, mass, smoothing length, density, and entropic variable of each particle. The file closes with the number of particles repeated, to be used as a safety check.