status_modify command

Warning

GPU support for this command has not been tested and may not work as expected.

Syntax

status_modify keyword value ...

  • one or more keyword/value pairs may be listed

  • keyword = lost or norm or flush or line or format

lost value = error or warn or ignore
norm value = yes or no
flush value = yes or no
line value = one or multi
format values = int string or float string or M string
  M = integer from 1 to N, where N = # of quantities being printed
  string = C-style format string

Examples

status_modify lost ignore flush yes
status_modify line multi format float %g

Description

Set options for how status information is computed and printed by Aspherix®.

Warning

These options apply to the currently defined status style. When you specify a status_style command, all status settings are restored to their default values, including those previously reset by a status_modify command. Thus if your input script specifies a status_style command, you should use the status_modify command after it.

The lost keyword determines whether Aspherix® checks for lost atoms each time it computes the status information and what it does if atoms are lost. An atom can be “lost” if it moves across a non-periodic simulation box boundary or if it moves more than a box length outside the simulation domain (or more than a processor sub-domain length) before reneighboring occurs. The latter case is typically due to bad dynamics, e.g. too large a timestep or huge forces and velocities. If the value is ignore, Aspherix® does not check for lost atoms. If the value is error or warn, Aspherix® checks and either issues an error or warning. The code will exit with an error and continue with a warning. A warning will only be issued once, the first time an atom is lost. This can be a useful debugging option.

Warning

For computational efficiency, this lost check is just a simple check if the total number of atoms in the system decreases. So for simulations where particles are continuously inserted, “lost” atoms might not be detected.

The norm keyword determines whether various status output values are normalized by the number of atoms or not, depending on whether it is set to yes or no. Different unit styles have different defaults for this setting (see below). Even if norm is set to yes, a value is only normalized if it is an “extensive” quantity, meaning that it scales with the number of atoms in the system. For the status keywords described by the doc page for the status_style command, all energy-related keywords are extensive. Other keywords such are “intensive” meaning their value is independent (in a statistical sense) of the number of atoms in the system and thus are never normalized. For status output values extracted from fixes and computes in a status_style custom command, the doc page for the individual fix or compute lists whether the value is “extensive” or “intensive” and thus whether it is normalized. Thermodynamic output values calculated by a variable formula are assumed to be “intensive” and thus are never normalized. You can always include a divide by the number of atoms in the variable formula if this is not the case.

The flush keyword invokes a flush operation after status info is written to the log file. This ensures the output in that file is current (no buffering by the OS), even if Aspherix® halts before the simulation completes.

The line keyword determines whether the status will be printed as a series of numeric values on one line or in a multi-line format with 3 quantities with text strings per line and a dashed-line header containing the timestep and CPU time. This modify option overrides the one and multi status_style settings.

The format keyword sets the numeric format of individual printed quantities. The int and float keywords set the format for all integer or floating-point quantities printed. The setting with a numeric value M (e.g. format 5 %10.4g) sets the format of the Mth value printed in each output line, e.g. the 5th column of output in this case. If the format for a specific column has been set, it will take precedent over the int or float setting.

Warning

The status output values step and atoms are stored internally as 8-byte signed integers, rather than the usual 4-byte signed integers. When specifying the “format int” keyword you can use a “%d”-style format identifier in the format string and Aspherix® will convert this to the corresponding “%lu” form when it is applied to those keywords. However, when specifying the “format M string” keyword for step and natoms, you should specify a string appropriate for an 8-byte signed integer, e.g. one with “%ld”.

Restrictions

none

Default

The option defaults are lost = ignore, norm = yes for unit style of lj, norm = no for unit style of real and metal, flush = no.

The defaults for the line and format options depend on the status style. For styles “one” and “custom”, the line and format defaults are “one”, “%8d”, and “%12.8g”. For style “multi”, the line and format defaults are “multi”, “%8d”, and “%14.4f”.