# 7.39. Restart

This section is referenced in the following other sections

- Examples: Restart Database
- Simulation Setup: Restart Reference

## 7.39.1. Restart Data

Scope

  Aria Region, Input_Output Region

Summary

  Describes the data required to output and input restart data for the enclosing region.

    begin Restart Data Label

       Additional Steps {=} List_of_steps...

       Additional Times {=} List_of_times...

       At Step n {increment | interval} {=} m

       At Time Dt1 {increment | interval} {=} Dt2

       At Wall Time Dt1 {increment | interval} {=} Dt2

       Component Separator Character {=} Separator

       Cycle Count {=} Count

       Database Name {=} StreamName

       Database Type {=} {catalyst | catalyst_exodus | cgns | dof | dof_exodus | exodus | exodusii | exonull | generated | genesis | null | parallel_exodus | textmesh}

       Debug Dump

       Decomposition Method {=} {block | cyclic | external | geom_kway | hsfc | kway | kway_geom | linear | map | metis_sfc | random | rcb | rib | variable}

       Exists {=} {abort | add_suffix | append | overwrite}

       File Cycle Count {=} Count

       Flush Interval {=} Option

       Input Database Name {=} StreamName

       Optional

       Output Database Name {=} StreamName

       Output On Signal {=} {sigabrt | sigalrm | sigfpe | sighup | sigill | sigint | sigkill | sigpipe | sigquit | sigsegv | sigterm | sigusr1 | sigusr2}

       Output Restart State {=} {off | on}

       Overlay Count {=} Count

       Overwrite {=} {false | no | off | on | true | yes}

       Property PropertyName {=} PropertyValue

       Restart {=} {auto}

       Restart Time {=} Time

       Start Time {=} Start_time

       Synchronize Output

       Shift To Start Time

       Termination Time {=} Final_time

       Timestep Adjustment Interval {=} Nsteps

       Use Dynamic Topology Io

       Use External Control

       Use Output Scheduler Timer_name

    end Restart Data Label

### 7.39.1.1. Line Commands

###### Additional Steps

Syntax

  Additional Steps {=} List_of_steps…

Summary

  Additional simulation steps when output should occur.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
List_of_steps | integer… | –

###### Additional Times

Syntax

  Additional Times {=} List_of_times…

Summary

  Additional simulation times when output should occur.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
List_of_times | real… | –

###### At Step

Syntax

  At Step n {increment | interval} {=} m

Summary

  Specify an output interval in terms of the internal iteration step count. The first step specifies the step count at the beginning of this interval and the second step specifies the output frequency to be used within this interval.

Parameter | Value | Default
--- | --- | ---
n | integer | –
Option | {increment | interval} | –
{=} | {= | are | is} | –
m | integer | –

###### At Time

Syntax

  At Time Dt1 {increment | interval} {=} Dt2

Summary

  Specify an output interval in terms of the internal simulation time. The first time specifies the time at the beginning of this time interval and the second time specifies the output frequency to be used within this interval.

Parameter | Value | Default
--- | --- | ---
Dt1 | real | –
Option | {increment | interval} | –
{=} | {= | are | is} | –
Dt2 | real | –

###### At Wall Time

Syntax

  At Wall Time Dt1 {increment | interval} {=} Dt2

Summary

  Write a restart file at a specific wall time since the start of the run. Time string format allows s, m, h, d for seconds, minutes, hours, days

Parameter | Value | Default
--- | --- | ---
Dt1 | string | –
Option | {increment | interval} | –
{=} | {= | are | is} | –
Dt2 | string | –

###### Component Separator Character

Syntax

  Component Separator Character {=} Separator

Summary

  The separator is the single character used to separate the output variable basename (e.g. “stress”) from the suffices (e.g. “xx”, “yy”) when displaying the names of the individual variable components. For example, the default separator is “_”, which results in names similar to “stress_xx”, “stress_yy”, … “stress_zx”. To eliminate the separator, specify an empty string (“”) or NONE.

Parameter | Value | Default
--- | --- | ---
{=} | {= | is} | –
Separator | string | –

###### Cycle Count

Syntax

  Cycle Count {=} Count

Summary

  Specify the number of restart steps which will be written to the restart database before previously written steps are overwritten. For example, if the cycle count is 5 and restart is written every 0.1 seconds, the restart system will write 0.1, 0.2, 0.3, 0.4, 0.5 to the database. It will then overwrite the first step with data from time 0.6, the second with time 0.7. At time 0.8, the database would contain data at times 0.6, 0.7, 0.8, 0.4, 0.5. Note that time will not necessarily be monotonically increasing on a database that specifies the cycle count.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Count | integer | –

###### Database Name

Syntax

  Database Name {=} StreamName

Summary

  The database containing the input and/or output restart data. If this analysis is being restarted, restart data will be read from this file. If the analysis is writing restart data, the data will be written to this file. It will be overwritten if it exists (after being read if applicable). If the filename begins with the ‘/’ character, it is an absolute path; otherwise, the path to the current directory will be prepended to the name. See also the ‘Input Database’ and ‘Output Database’ commands.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
StreamName | string | –

###### Database Type

Syntax

  Database Type {=} {catalyst | catalyst_exodus | cgns | dof | dof_exodus | exodus | exodusii | exonull | generated | genesis | null | parallel_exodus | textmesh}

Summary

  The database type/format used for the restart file.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
DatabaseTypes | {catalyst | catalyst_exodus | cgns | dof | dof_exodus | exodus | exodusii | exonull | generated | genesis | null | parallel_exodus | textmesh} | –

###### Debug Dump

Syntax

  Debug Dump

Summary

  Specify whether the restart system will write the restart data immediately after reading the restart data if the run is restarting. The output data can be compared with the restart input data to determine whether they match.

###### Decomposition Method

Syntax

  Decomposition Method {=} {block | cyclic | external | geom_kway | hsfc | kway | kway_geom | linear | map | metis_sfc | random | rcb | rib | variable}

Summary

  The decomposition algorithm to be used to partition elements to each processor in a parallel run.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Method | {block | cyclic | external | geom_kway | hsfc | kway | kway_geom | linear | map | metis_sfc | random | rcb | rib | variable} | –

###### Exists

Syntax

  Exists {=} {abort | add_suffix | append | overwrite}

Summary

  Specify the behavior when creating this database and there is an existing file with the same name. The default behavior is “OVERWRITE” which deletes the existing file and creates a new file of the same name. “APPEND” will (if possible) append the new data to the end of the existing file. “ABORT” will print an error message and end the analysis. “ADD_SUFFIX” will add a suffix to the file name and output to that file.

Parameter | Value | Default
--- | --- | ---
{=} | {= | is} | –
Option2 | {abort | add_suffix | append | overwrite} | –

###### File Cycle Count

Syntax

  File Cycle Count {=} Count

Summary

  Each restart dump will be written to a separate file suffixed with A,B, … The count specifies how many separate files are used before the cycle repeats. For example, if “FILE CYCLE COUNT = 3” is specified, the restart dumps would be written to file-A.rs, file-B.rs, file-C.rs, file-A.rs, … The maximum value for the cycle count is 26.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Count | integer | –

###### Flush Interval

Syntax

  Flush Interval {=} Option

Summary

  The minimum time interval (in seconds) at which output will be explicitly flushed to disk. The default is 10 seconds.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Option | integer | 10

###### Input Database Name

Syntax

  Input Database Name {=} StreamName

Summary

  The database containing the input restart data. If this analysis is being restarted, restart data will be read from this file. See also the ‘Database’ and ‘Output Database’ commands.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
StreamName | string | –

###### Optional

Syntax

  Optional

Summary

  The database will be read if it exists, but it is not an error if there is no restart database to read for this region during a restarted analysis.

###### Output Database Name

Syntax

  Output Database Name {=} StreamName

Summary

  The database containing the output restart data. If the analysis is writing restart data, the data will be written to this file. It will be overwritten if it exists. See also the ‘Database’ and ‘Input Database’ commands.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
StreamName | string | –

###### Output On Signal

Syntax

  Output On Signal {=} {sigabrt | sigalrm | sigfpe | sighup | sigill | sigint | sigkill | sigpipe | sigquit | sigsegv | sigterm | sigusr1 | sigusr2}

Summary

  When the specified signal is raised, the output stream associated with this block will be output.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Signals | {sigabrt | sigalrm | sigfpe | sighup | sigill | sigint | sigkill | sigpipe | sigquit | sigsegv | sigterm | sigusr1 | sigusr2} | –

###### Output Restart State

Syntax

  Output Restart State {=} {off | on}

Summary

  Outputs the restarted state to the new restarted results file

Description

  NOTE: This command must be placed at the Sierra scope of the input file. Allows the analyst to visualize the restarted state for debugging

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Option | {off | on} | –

###### Overlay Count

Syntax

  Overlay Count {=} Count

Summary

  Specify the number of restart outputs which will be overlaid on top of the last written step. For example, if restarts are being output every 0.1 seconds and the overlay count is specified as 2, then restart will write times 0.1 to step 1 of the database. It will then write 0.2 and 0.3 also to step 1. It will then increment the database step and write 0.4 to step 2; overlay 0.5 and 0.6 on step 2… At the end of the analysis, assuming it runs to completion, the database would have times 0.3, 0.6, 0.9, … However, if there were a problem during the analysis, the last step on the database would contain an intermediate step.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Count | integer | –

###### Overwrite

Syntax

  Overwrite {=} {false | no | off | on | true | yes}

Summary

  (DEPRECATED, Use EXISTS) Specify whether the restart database should be overwritten if it exists. The default behavior is to overwrite unless this command is specified in the restart block and either off, false, or no is specified.

Parameter | Value | Default
--- | --- | ---
{=} | {= | is} | –
Option2 | {false | no | off | on | true | yes} | –

###### Property

Syntax

  Property PropertyName {=} PropertyValue

Summary

  Define a database property named “PropertyName” with the value “PropertyValue”. If PropertyValue consists of all digits, it will define an integer property. If PropertyValue is “true” or “yes” or “false” or “no”, it will define a logical property; otherwise it will define a string property. If PropertyName consists of multiple strings, they will be concatenated together with “_” separating the individual words. Supported properties are typically database dependent; Current properties are:

  - COMPRESSION_LEVEL = [0..9]

  - COMPRESSION_SHUFFLE = true|false|on|off

  - FILE_TYPE = netcdf4 (forces use of netcdf-4 hdf5-based file)

  - INTEGER_SIZE_DB = 4|8

  - INTEGER_SIZE_API = 4|8

  - LOGGING = true|false|on|off

  - MAX_NAME_LENGTH = value

Parameter | Value | Default
--- | --- | ---
PropertyName | string | –
{=} | {= | are | is} | –
PropertyValue | string | –

###### Restart

Syntax

  Restart {=} {auto}

Summary

  Specify automatic restart file read.

Description

  NOTE: This command must be placed at the Sierra scope of the input file.

  Specify that the analysis should be restarted from the last common time on all restart databases for each Region in the analysis. In addition to this line command, each Region in the analysis (strictly, only the region(s) that will be restarted) must have a restart block specifying the database to read the restart state data.

  By default, use of this command will not cause output files (e.g., results, history, heartbeat, restart) to be overwritten. Instead output files will be written with the same basename and the suffix `-s000*`. Common visualization packages are written to handle this file organization gracefully in order for the user to view all results seamlessly.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
{auto} | {auto | automatic} | –

###### Restart Time

Syntax

  Restart Time {=} Time

Summary

  Specify restart file read at a specified time.

Description

  NOTE: This command must be placed at the Sierra scope of the input file.

  Specify the time that the analysis will be restarted. In addition to this line command, each Region in the analysis (strictly, only the region(s) that will be restarted) must have a restart block specifying the database to read the restart state data. The restart ‘time’ must be greater than zero and less than or equal to the termination time.

  By default, use of this command will cause previous output files (e.g., results, history, heartbeat, restart) to be overwritten. If this command is chosen, the onus is placed on the user to ensure that previous output files are not overwritten.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Time | real | –

###### Start Time

Syntax

  Start Time {=} Start_time

Summary

  Specify the time to start outputting results from this output request block. This time overrides all ‘at time’ and ‘at step’ specifications.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Start_time | real | –

###### Synchronize Output

Syntax

  Synchronize Output

Summary

  In an analysis with multiple regions, it is sometimes desirable to synchronize the output of results data between the regions. This can be done by adding the SYNCHRONIZE OUTPUT command line to the results output block. If a results block has this set, then it will write output whenever a previous region writes output. The ordering of regions is based on the order in the input file, algorithmic considerations, or by solution control specifications.

  Although the USE OUTPUT SCHEDULER command line can also synchronize output between regions, the SYNCHRONIZE OUTPUT command line will synchronize the output with regions where the output frequency is not under the direct control of the Sierra IO system. Examples of this are typically coupled applications where one or more of the codes are not Sierra-based applications such as Alegra and CTH. A results block with SYNCHRONIZE OUTPUT specified will also synchronize its output with the output of the external code.

  The SYNCHRONIZE OUTPUT command can be used with other output scheduling commands such as time-based or step-based output specifications.

###### Shift To Start Time

Syntax

  Shift To Start Time

Summary

  The shift to start time option allows a user to shift the restart time to the start time of the current region. An example use case would be if a restart time of 0.5 is specified, but the user would like to start the simulation at time 1.0.

###### Termination Time

Syntax

  Termination Time {=} Final_time

Summary

  Specify the time to stop outputting results from this output request block.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Final_time | real | –

###### Timestep Adjustment Interval

Syntax

  Timestep Adjustment Interval {=} Nsteps

Summary

  Specify the number of steps to ‘look ahead’ and adjust the timestep to ensure that the specified output times or simulation end time will be hit ‘exactly’.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Nsteps | integer | –

###### Use Dynamic Topology Io

Syntax

  Use Dynamic Topology Io

Summary

  Specify that the app use IO for dynamic topology modifications where the output files are stored in a single database. Legacy file format for dynamically changing topology results in the creation of multiple files for each output on a mesh modification. This option leverages the ability of netCDF to create mesh groups within a single database and concatenate all mesh files into one. The names of each mesh group are of the form IOSS_MESH_GROUP-??? where ??? is the 1-based output index 1, 2, …, 10, …., 100, … Please note that netCDF has a current limit of 65,536 groups

###### Use External Control

Syntax

  Use External Control

Summary

  Do not schedule any results output but instead depend on an externally coupled application to explicitly call for results output.

###### Use Output Scheduler

Syntax

  Use Output Scheduler Timer_name

Summary

  Associates a predefined output scheduler with this output block (results, restart, heartbeat, or history).

Parameter | Value | Default
--- | --- | ---
Timer_name | string | –

## 7.39.2. Restart Time

Syntax

  Restart Time {=} Time

Summary

  Specify restart file read at a specified time.

Description

  NOTE: This command must be placed at the Sierra scope of the input file.

  Specify the time that the analysis will be restarted. In addition to this line command, each Region in the analysis (strictly, only the region(s) that will be restarted) must have a restart block specifying the database to read the restart state data. The restart ‘time’ must be greater than zero and less than or equal to the termination time.

  By default, use of this command will cause previous output files (e.g., results, history, heartbeat, restart) to be overwritten. If this command is chosen, the onus is placed on the user to ensure that previous output files are not overwritten.

Parameter | Value | Default
--- | --- | ---
{=} | {= | are | is} | –
Time | real | –