Next: , Previous: Usage, Up: Top



3 Global Parameters

This section describes all of the global parameters that affect simulation. All of these parameters are set by the parameter command with parameter key=value ....

Simulation parameters:

— User Option: time_step val

Sets the step-size for simulation and numerical integration.

Convergence parameters:

— User Option: position_tolerance val

Set the threshold for maximum delta in position for considering convergence.

— User Option: velocity_tolerance val

Set the threshold for maximum delta in velocity for considering convergence.

— User Option: energy_tolerance val

Set the threshold for maximum delta in energy for considering convergence.

Physics parameters:

— User Option: damping val

Viscous damping coefficient that applies a linearly dependent force in the opposite direction of the velocity vector.

— User Option: temperature val

Temperature is used to randomly perturb the position of all objects after each iteration. Random perturbation is means by which annealing is simulated.

— User Option: repulsion_coeff val
— User Option: repulsion_constant val

Object proximity is modeled as spring repulsion. repulsion_coeff is the repulsion spring coefficient for a compressed spring, which models the collision of soft objects. repulsion_constant is a constant additive force term for the spring that is compressed to model the hardness of the boundary.

Gravity parameters:

— User Option: x_gravity_coeff val
— User Option: y_gravity_coeff val
— User Option: z_gravity_coeff val

The linear spring coefficient for gravity wells in the x,y,z direction.

— User Option: x_gravity_constant val
— User Option: y_gravity_constant val
— User Option: z_gravity_constant val

The constant force term for gravity wells in the x,y,z directions. Setting this to non-zero helps attract objects closer to the well.

Feedback parameters:

— User Option: precision val

Sets the precision of floating-point values that are printed.

— User Option: watch_objects val

Set to 1 to print out object position updates with every iteration.

— User Option: watch_energy val

Set to 1 to print out object position updates with every iteration.

— User Option: report_iterations val

Set to 1 to report number of iterations in numerical convergence routines.