Execution

Introduction

SAS4A/SASSYS-1 runs as a DOS executable at the Windows command prompt or as a command-line tool in Unix or Linux shells.

Input Files

A text-based input file that describes the problem to be solved is required for all SAS4A/SASSYS-1 calculations. This text file is read from standard input. An optional binary restart file must also be provided if a simulation is being restarted from a previously saved state.

Restart

A simulation may be continued from where it ended if an input file with a RESTART declaration is provided along with an existing restart file generated by a prior execution. SAS4A/SASSYS-1 makes a distinction between an output and an input restart file:

RESTART File (fort.17) — output

This RESTART file is created by SAS4A/SASSYS-1 and it contains all of the data needed to continue a calculation from where it left off. RESTART files are saved at the end of steady-state initialization and after every NSTEP main time steps. If NSTEP is zero, no restart files are saved.

RESTART File (fort.18) — input

An input RESTART file must be provided the user if a simulation is being restarted from a previously saved state. In this case, the saved RESTART file must be renamed from fort.17 to fort.18 and an appropriate restart input file must be provided on standard input.