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Global Control

The general simulation parameters can be defined by the global block. This operator allows to define all control parameters such as the time step, the log/dump/restart frequencies, the log type, and any additional parameter that can be taken as an input by operators called during the simulation. 

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simulation:
  name: MySimulation
  body:
    - print_logo_banner                                  
    - hw_device_init                                     
    - make_empty_grid                                     
    - grid_flavor                                         
    - global                                             
    - [...]
    - simulation_epilog
    - hw_device_finalize

Below is the default definition of the global block as defined in data/config/main-config.msp:

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global:
  timestep: 0
  physical_time: 0.
  dt: 1.0e-3 ps
  rcut_inc: 1.0 ang
  simulation_end_iteration: 10000
  simulation_log_frequency: 10
  log_mode: mechanical
  simulation_dump_frequency: 1000
  simulation_dump_thermo_frequency: 10
  analysis_dump_frequency: 0
  trigger_thermo_state: true
  compute_loop_continue: true
  init_temperature: -1.0
  scale_temperature: -1.0
  enable_load_balance: true
  simulation_load_balance_frequency: 100  
  trigger_cost_model_fitting: false
  cost_model_coefs: [ 0.0 , 0.0 , 1.0 , 0.0 ]
  enable_task_graph: false
  enable_grid_compact: true

The table below contains the descriptions of these parameters.

Parameter Description Type Default
timestep Starting time-step int 0
physical_time Starting physical time float 0.
dt Time-step float 1.0e-3 ps
rcut_inc Extra distance beyond cutoff float 1.0 ang
simulation_end_iteration Ending time-step int 10000
simulation_log_frequency Screen log frequency int 10
log_mode Log mode string mechanical (other choices are default or chemistry)
simulation_dump_frequency Dump data frequency int 1000
simulation_dump_thermo_frequency File log frequency int 10
analysis_dump_frequency Analysis frequency int 0
trigger_thermo_state Thermodynamic state calculation bool true
compute_loop_continue Whether loop continues or not bool 0
init_temperature Initial temperature float -1.0
scale_temperature Scaling temperature float -1.0
enable_load_balanceg Allows load balancing bool true
simulation_load_balance_frequency Load balancing frequency int 100
trigger_cost_model_fitting Trigger cost model fitting bool false
cost_model_coefs Cost model coefs list [ 0.0 , 0.0 , 1.0 , 0.0 ]
enable_task_graph Enables task graph bool false
enable_grid_compact Enables grid compaction bool true

In practice, the user doesn't need to think about some of these variables as they only serve as input for the simulation initialization. Here's a minimal global block you can use to start your simulation with.

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global:
  dt: 1.0e-3 ps
  rcut_inc: 1.0 ang
  simulation_end_iteration: 1000
  simulation_log_frequency: 10
  simulation_dump_thermo_frequency: 10  
  simulation_dump_frequency: 1000
  analysis_dump_frequency: 0