Checkpoints
NOTE: This is likely deprecated (old checkpointing system that never worked). See 4.0 subdocument (Chekpointing.md) for the more recent implementation.
TODO - Incomplete - Add in content from related checkpoint files
A checkpoint is a state save of a long simulation that is only partially completed. Checkpoints can be done periodically either based on the elapsed wall-clock time or elapsed simulation time. When a checkpoint save is performed, a stream dump of the model is output to a checkpoint file. At the time of each checkpoint, the stream file contains the complete internal state of the model, which includes
- global variables including module globals
- internal system states including indexes, multiprocessing states, schedules, loadshapes, end uses, and transforms
- objects including all the internal state variables
- open file handles and flushed positions
- all other data required to ensure that the simulation can be resumed at the checkpoint
The following global variables are defined for checkpoint saving:
| Variable | Description |
|---|---|
| checkpoint_type | This defines the type of checkpoint used. Valid values are {NONE , WALL , SIM}. WALL indicates that the checkpoint_interval is based on the wall clock time, and SIM indicates that the checkpoint_interval is based on the simulation clock time. The default value is NONE. |
| checkpoint_file | This defines the name of the checkpoint to use. The checkpoint files will be named using a sequence number appended to the checkpoint file name, e.g., checkpoint_file.seq. The default checkpoint file name is the base name of the main GLM file. |
| checkpoint_interval | This defines the interval in seconds between checkpoint saves. The default value is 3600 , or one hour, when checkpoint_type is WALL and 86400 , or one day, when checkpoint_type is SIM. |
| checkpoint_keepall | If this value is TRUE , all the checkpoint files are kept. If the value is FALSE , only the last checkpoint file saved is kept and all previous checkpoint files are delete. The default value is FALSE , meaning that only the last checkpoint file is kept. |
| checkpoint_seqnum | This value identifies the sequence number of the next checkpoint file. The default is 0. |
Checkpoints are enabled by setting the global variable checkpoint_type to either WALL or SIM.
A checkpoint file can be loaded and resumed using the stream command line options:
host% gridlabd -D checkpoint_file="savefile" -D checkpoint_interval=3600 -D checkpoint_type=WALL
Examples
Set the checkpoint save to the file test every 5 minutes of wall clock time:
#set checkpoint_type=WALL
#set checkpoint_file=test
#set checkpoint_interval=300
Set the checkpoint save to the GLM file name every hour of simulation time and keep all checkpoints:
#set checkpoint_type=SIM
#set checkpoint_interval=3600
#set checkpoint_keepall=TRUE