6. Parameters

6.1. Parameters

Parameters are set globally, on devices, or on regions of a device. The models on each device region are automatically updated whenever parameters change.

devsim.set_parameter(device="device", region="region",
  name="ThermalVoltage", value=0.0259)

They may also be used to control program behavior, as listed in Parameters controlling program behavior:

Table 6.1 Parameters controlling program behavior
Parameter	Description
`debug_level`	`info`, `verbose` Example
`edge_couple_model`	Cylindrical coordinate systems
`edge_node0_volume_model`	Cylindrical coordinate systems
`edge_node1_volume_model`	Cylindrical coordinate systems
`element_edge_couple_model`	Cylindrical coordinate systems
`element_node0_volume_model`	Cylindrical coordinate systems
`element_node1_volume_model`	Cylindrical coordinate systems
`extended_equation`	`value=False` Extended precision equation evaluation
`extended_model`	`value=False` Extended precision model evaluation
`extended_solver`	`value=False` Extended precision matrix and RHS assembly and error evaluations. Linear solver and circuit assembly is still double precision``
`info`	Determine loaded math libraries
`node_volume_model`	Cylindrical coordinate systems
`solver_callback`	Custom direct solver
`surface_area_model`	Model for integration of flux and hybrid interfaces.
`threads_available`	`value=1`, Command help
`threads_task_size`	`value=?`, Command help

6.2. Environment variables

Environment variables to control program behavior are listed in Environment controlling program behavior:. Please consult Release notes: for the most up to information concerning their usage.

Table 6.2 Environment controlling program behavior
Environment Variable	Description
`DEVSIM_MATH_LIBS`	List of BLAS/LAPACK libraries to load instead of system defaults
`DEVSIM_NEW_SYMBOLIC`	When set, do a new symbolic matrix factorization during direct solve iterations, Symbolic factorization reuse
`CONDA_PREFIX`	For Anaconda `Python` installations, this is the location of the `devsim_data` directory.
`VIRTUAL_ENV`	For `pip`-based `Python` installations, this is the location of the `devsim_data` directory.

6.3. Notes

Parameters may be used in model expressions. If a parameter is not found, then DEVSIM will also look for a circuit node by the name used in the model expression.