Output_global block

This block contains parameters which should be applied to all output blocks. See EPOCH input deck for more information on the input deck.

With the introduction of multiple output blocks, there are now a few parameters that only make sense to be applied globally across all output blocks. To accommodate this, a new block named “output_global” has been added. Most of the parameters accepted by this block have the same meaning as those in the “output” block except that they are applied to all “output” blocks.

The parameters that can be specified in the “output_global” block are as follows:

• force_first_to_be_restartable - Logical flag which determines whether the file written at time zero is a restart dump. The default value is “F”.
• force_last_to_be_restartable - Force the code to override other output settings and make the last output dump it writes be a restart dump. Any internal condition which causes the code to terminate will make the code write a restart dump, but code crashes or scheduler terminations will not cause the code to write a restart dump. “force_final_to_be_restartable” is accepted as a synonym. The default value is “T”.
• dump_first - Logical flag which determines whether to write an output file immediately after initialising the simulation. The default is “F”.
• dump_last - Logical flag which determines whether to write an output file just before ending the simulation. The default is “T” if an output block exists in the input deck and “F” otherwise. “dump_final” is accepted as a synonym.
• time_start - Floating point parameter which specifies the simulation time at which to start considering output for all output blocks. Note that if “dump_first” or “dump_last” are set to true for any block then dumps will occur at the first or last timestep regardless of the value of this parameter. This also applies to the three following parameters. The default value is 0.
• time_stop - Floating point parameter which specifies the simulation time at which to stop considering output for all output blocks. The default value is the largest possible float.
• nstep_start - Integer parameter which specifies the step number at which to start considering output for the block. The default value is 0.
• nstep_stop - Integer parameter which specifies the step number at which to stop considering output for the block. The default value is the largest possible integer.
• walltime_start - Floating point parameter which specifies the elapsed walltime in seconds at which to start considering output for all output blocks. Note that if dump_first or dump_last are set to true for any blocks then dumps will occur at the first or last timestep regardless of the value of the walltime_start parameter. The default value is 0.
• walltime_stop - Floating point parameter which specifies the elapsed walltime in seconds at which to stop considering output all output blocks. The default value is the largest possible float.
• sdf_buffer_size - Integer parameter. When writing particle data to an SDF file, the data is first transferred into an output buffer. The size of this buffer can have a big impact on the overall speed of writing dump files. This parameter allows the size of the buffer to be specified in bytes. The default value is 67108864 (64 MB).
• filesystem - String parameter. Some filesystems can be unreliable when performing parallel I/O. Often this is fixable by prefixing the filename with ‘ufs’ or ‘nfs’. This parameter supplies the prefix to be used. The default value is an empty string.
• use_offset_grid - When using moving windows some visualisation programs (notably VisIt) show the motion of the window by moving the visualisation window rather than by changing the x-axis. Setting this option to “T” causes the code to write another grid which always gives the offset relative to the left hand edge of the window rather than the true origin. Performs no function when not using the moving window. The default value is “F”.
• dump_first_after_restart - Logical flag to enable a dump to occur immediately after restart. In the past, a dump_first flag in the output block would cause an output dump immediately after restarting. Since this is rarely the desired behaviour, the flag is now ignored when restarting. To force a dump to occur immediately after restart, set dump_first_after_restart = T in the output block. The default value is “F”.