14. Command Reference

14.1. Circuit Commands

Commands are for adding circuit elements to the simulation.

devsim.add_circuit_node(name, value, variable_update)

Adds a circuit node for use in circuit or multi-device simulation

Parameters

name (str) – Name of the circuit node being created
value (Float, optional) – initial value (default 0.0)
variable_update ({'default', 'log_damp', 'positive'}) – update type for circuit variable

devsim.circuit_alter(name, param, value)

Alter the value of a circuit element parameter

Parameters

name (str) – Name of the circuit node being created
param (str, optional) – parameter being modified (default ‘value’)
value (Float) – value for the parameter

devsim.circuit_element(name, value, n1, n2, acreal, acimag)

Adds a circuit element external to the devices

Parameters

name (str) – Name of the circuit element being created. A prefix of ‘V’ is for voltage source, ‘I’ for current source, ‘R’ for resistor, ‘L’ for inductor, and ‘C’ for capacitor.
value (Float, optional) – value for the default parameter of the circuit element (default 0.0)
n1 (str) – circuit node
n2 (str) – circuit node
acreal (Float, optional) – real part of AC source for voltage (default 0.0)
acimag (Float, optional) – imag part of AC source for voltage (default 0.0)

devsim.circuit_node_alias(node, alias)

Create an alias for a circuit node

Parameters

node (str) – circuit node being aliased
alias (str) – alias for the circuit node

devsim.delete_circuit(): Deletes any present circuit and its solutions.

devsim.get_circuit_equation_number(node)

Returns the row number correspond to circuit node in a region. Values are only valid when during the course of a solve.

Parameters: node (str) – circuit node

devsim.get_circuit_node_list(): Gets the list of the nodes in the circuit.

devsim.get_circuit_node_value(solution, node)

Gets the value of a circuit node for a given solution type.

Parameters

solution (str, optional) – name of the solution. ‘dcop’ is the name for the DC solution (default ‘dcop’)
node (str) – circuit node of interest

devsim.get_circuit_solution_list(): Gets the list of available circuit solutions.

devsim.set_circuit_node_value(solution, node, value)

Sets the value of a circuit node for a given solution type.

Parameters

solution (str, optional) – name of the solution. ‘dcop’ is the name for the DC solution (default ‘dcop’)
node (str) – circuit node of interest
value (Float, optional) – new value (default 0.0)

14.2. Equation Commands

Commands for manipulating equations on contacts, interface, and regions

devsim.contact_equation(device, contact, name, circuit_node, edge_charge_model, edge_current_model, edge_model, edge_volume_model, element_charge_model, element_current_model, element_model, volume_node0_model, volume_node1_model, node_charge_model, node_current_model, node_model)

Create a contact equation on a device

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
name (str) – Name of the contact equation being created
circuit_node (str, optional) – Name of the circuit we integrate the flux into
edge_charge_model (str, optional) – Name of the edge model used to determine the charge at this contact
edge_current_model (str, optional) – Name of the edge model used to determine the current flowing out of this contact
edge_model (str, optional) – Name of the edge model being integrated at each edge at this contact
edge_volume_model (str, optional) – Name of the edge model being integrated over the volume of each edge on the contact
element_charge_model (str, optional) – Name of the element edge model used to determine the charge at this contact
element_current_model (str, optional) – Name of the element edge model used to determine the current flowing out of this contact
element_model (str, optional) – Name of the element edge model being integrated at each edge at this contact
volume_node0_model (str, optional) – Name of the element model being integrated over the volume of node 0 of each edge on the contact
volume_node1_model (str, optional) – Name of the element model being integrated over the volume of node 1 of each edge on the contact
node_charge_model (str, optional) – Name of the node model used to determine the charge at this contact
node_current_model (str, optional) – Name of the node model used to determine the current flowing out of this contact
node_model (str, optional) – Name of the node model being integrated at each node at this contact

devsim.custom_equation(name, procedure)

Custom equation assembly. See Custom Matrix assembly for a description of how the function should be structured.

Parameters

name (str) – Name of the custom equation being created
procedure (str) – The procedure to be called

devsim.delete_contact_equation(device, contact, name)

This command deletes an equation from a contact.

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
name (str) – Name of the contact equation being deleted

devsim.delete_equation(device, region, name)

This command deletes an equation from a region.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the equation being deleted

devsim.delete_interface_equation(device, interface, name)

This command deletes an equation from an interface.

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
name (str) – Name of the interface equation being deleted

devsim.equation(device, region, name, variable_name, node_model, edge_model, edge_volume_model, time_node_model, element_model, volume_node0_model, volume_node1_model, variable_update)

Specify an equation to solve on a device

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the equation being created
variable_name (str) – Name of the node solution being solved
node_model (str, optional) – Name of the node model being integrated at each node in the device volume
edge_model (str, optional) – Name of the edge model being integrated over each edge in the device volume
edge_volume_model (str, optional) – Name of the edge model being integrated over the volume of each edge in the device volume
time_node_model (str, optional) – Name of the time dependent node_model being integrated at each node in the device volume
element_model (str, optional) – Name of the element model being integrated over each edge in the device volume
volume_node0_model (str, optional) – Name of the element model being integrated over the volume of node 0 of each edge on the contact
volume_node1_model (str, optional) – Name of the element model being integrated over the volume of node 1 of each edge on the contact
variable_update ({'default', 'log_damp', 'positive'}) – update type for circuit variable

Notes

The integration variables can be changed in 2D for cylindrical coordinate systems by setting the appropriate parameters as described in Cylindrical Coordinate Systems.

In order to set the node volumes for integration of the edge_volume_model, it is possible to do something like this:

devsim.edge_model(device=”device”, region=”region”, name=”EdgeNodeVolume”, equation=”0.5*SurfaceArea*EdgeLength”) devsim.set_parameter(name=”edge_node0_volume_model”, value=”EdgeNodeVolume”) devsim.set_parameter(name=”edge_node1_volume_model”, value=”EdgeNodeVolume”)

devsim.get_contact_equation_command(device, contact, name)

This command gets the options used when creating this contact equation.

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
name (str) – Name of the contact equation being command options returned

devsim.get_contact_equation_list(device, contact)

This command gets a list of equations on the specified contact.

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command

devsim.get_equation_command(device, region, name)

This command gets the options used when creating this equation.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the equation being command options returned

devsim.get_equation_list(device, region)

This command gets a list of equations on the specified region.

Parameters

device (str) – The selected device
region (str) – The selected region

devsim.get_equation_numbers(device, region, equation, variable)

Returns a list of the equation numbers corresponding to each node in a region. Values are only valid when during the course of a solve.

Parameters

device (str) – The selected device
region (str) – The selected region
equation (str, optional) – Name of the equation
variable (str, optional) – Name of the variable

devsim.get_interface_equation_command(device, interface, name)

This command gets the options used when creating this interface equation.

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
name (str) – Name of the interface equation being command options returned

devsim.get_interface_equation_list(device, interface)

This command gets a list of equations on the specified interface.

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command

devsim.interface_equation(device, interface, name, name0, name1, interface_model, type)

Command to specify an equation at an interface

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
name (str) – Name of the interface equation being created
name0 (str, optional) – Name of the equation coupling in region 0 being created (default ‘name’)
name1 (str, optional) – Name of the equation coupling in region 1 being created (default ‘name’)
interface_model (str) – When specified, the bulk equations on both sides of the interface are integrated together. This model is then used to specify how nodal quantities on both sides of the interface are balanced
type ({'continuous', 'fluxterm', 'hybrid'} required) – Specifies the type of boundary condition

14.3. Geometry Commands

Commands for getting information about the device structure.

devsim.get_contact_list(device)

Gets a list of contacts on a device.

Parameters: device (str) – The selected device

devsim.get_device_list(): Gets a list of devices on the simulation.

devsim.get_element_node_list(device, region, contact, interface, reorder)

Gets a list of nodes for each element on a device, region, contact, or interface.

Parameters

device (str) – The selected device
region (str) – The selected region
contact (str, optional) – If specified, gets the element nodes for the contact on the specified region
interface (str, optional) – If specified, gets the element nodes for the interface on the specified region
reorder (bool, optional) – If specified, reorders the element nodes in a manner compatible in meshing software (default False)

devsim.get_interface_list(device)

Gets a list of interfaces on a device.

Parameters: device (str) – The selected device

devsim.get_region_list(device, contact, interface)

Gets a list of regions on a device, contact, or interface.

Parameters

device (str) – The selected device
contact (str, optional) – If specified, gets the name of the region belonging to this contact on the device
interface (str, optional) – If specified, gets the name of the regions belonging to this interface on the device

devsim.reset_devsim(): Resets all data for clean restart.

14.4. Material Commands

Commands for manipulating parameters and material properties

devsim.add_db_entry(material, parameter, value, unit, description)

Adds an entry to the database

Parameters

material (str) – Material name requested. global refers to all regions whose material does not have the parameter name specified
parameter (str) – Parameter name
value (str) – Value assigned for the parameter
unit (str) – String describing the units for this parameter name
description (str) – Description of the parameter for this material type.

Notes

The devsim.save_db() command is used to commit these added entries permanently to the database.

devsim.close_db(): Closes the database so that its entries are no longer available

devsim.create_db(filename)

Create a database to store material properties

Parameters: filename (str) – filename to create for the db

devsim.get_db_entry(material, parameter)

This command returns a list containing the value, unit, and description for the requested material db entry

Parameters

material (str) – Material name
parameter (str) – Parameter name

devsim.get_dimension(device)

Get the dimension of the device

Parameters: device (str, optional) – The selected device

devsim.get_material(device, region, contact)

Returns the material for the specified region

Parameters

device (str, optional) – The selected device
region (str, optional) – The selected region
contact (str, optional) – Contact on which to apply this command

devsim.get_parameter(device, region, name)

Get a parameter on a region, device, or globally.

Parameters

device (str, optional) – The selected device
region (str, optional) – The selected region
name (str) – Name of the parameter name being retrieved

Notes

Note that the device and region options are optional. If the region is not specified, the parameter is retrieved for the entire device. If the device is not specified, the parameter is retrieved for all devices. If the parameter is not found on the region, it is retrieved on the device. If it is not found on the device, it is retrieved over all devices.

devsim.get_parameter_list(device, region)

Get list of parameter names on region, device, or globally

Parameters

device (str, optional) – The selected device
region (str, optional) – The selected region

Notes

Note that the device and region options are optional. If the region is not specified, the parameter is retrieved for the entire device. If the device is not specified, the parameter is retrieved for all devices. Unlike the devsim.getParameter(), parameter names on the the device are not retrieved if they do not exist on the region. Similarly, the parameter names over all devices are not retrieved if they do not exist on the device.

devsim.open_db(filename, permissions)

Open a database storing material properties

Parameters

filename (str) – filename to create for the db
permissions ({'readonly', 'readwrite'}) – permissions on the db

devsim.save_db(): Saves any new or modified db entries to the database file

devsim.set_material(device, region, contact, material)

Sets the new material for a region

Parameters

device (str, optional) – The selected device
region (str, optional) – The selected region
contact (str, optional) – Contact on which to apply this command
material (str) – New material name

devsim.set_parameter(device, region, name, value)

Set a parameter on region, device, or globally

Parameters

device (str, optional) – The selected device
region (str, optional) – The selected region
name (str) – Name of the parameter name being retrieved
value (any) – value to set for the parameter

Notes

Note that the device and region options are optional. If the region is not specified, the parameter is set for the entire device. If the device is not specified, the parameter is set for all devices.

14.5. Meshing Commands

Commands for reading and writing meshes

devsim.add_1d_contact(material, mesh, name, tag)

Add a contact to a 1D mesh

Parameters

material (str) – material for the contact being created
mesh (str) – Mesh to add the contact to
name (str) – Name for the contact being created
tag (str) – Text label for the position to add the contact

devsim.add_1d_interface(mesh, tag, name)

Add an interface to a 1D mesh

Parameters

mesh (str) – Mesh to add the interface to
tag (str) – Text label for the position to add the interface
name (str) – Name for the interface being created

devsim.add_1d_mesh_line(mesh, tag, pos, ns, ps)

Add a mesh line to a 1D mesh

Parameters

mesh (str) – Mesh to add the line to
tag (str, optional) – Text label for the position
pos (str) – Position for the mesh point
ns (Float, optional) – Spacing from this point in the negative direction (default ps value)
ps (Float) – Spacing from this point in the positive direction

devsim.add_1d_region(mesh, tag1, tag2, region, material)

Add a region to a 1D mesh

Parameters

mesh (str) – Mesh to add the line to
tag1 (str) – Text label for the position bounding the region being added
tag2 (str) – Text label for the position bounding the region being added
region (str) – Name for the region being created
material (str) – Material for the region being created

devsim.add_2d_contact(name, material, mesh, region, xl, xh, yl, yh, bloat)

Add an interface to a 2D mesh

Parameters

name (str) – Name for the contact being created
material (str) – material for the contact being created
mesh (str) – Mesh to add the contact to
region (str) – Name of the region included in the contact
xl (Float, optional) – x position for corner of bounding box (default -MAXDOUBLE)
xh (Float, optional) – x position for corner of bounding box (default +MAXDOUBLE)
yl (Float, optional) – y position for corner of bounding box (default -MAXDOUBLE)
yh (Float, optional) – y position for corner of bounding box (default +MAXDOUBLE)
bloat (Float, optional) – Extend bounding box by this amount when search for mesh to include in region (default 1e-10)

devsim.add_2d_interface(mesh, name, region0, region1, xl, xh, yl, yh, bloat)

Add an interface to a 2D mesh

Parameters

mesh (str) – Mesh to add the interface to
name (str) – Name for the interface being created
region0 (str) – Name of the region included in the interface
region1 (str) – Name of the region included in the interface
xl (Float, optional) – x position for corner of bounding box (default -MAXDOUBLE)
xh (Float, optional) – x position for corner of bounding box (default +MAXDOUBLE)
yl (Float, optional) – y position for corner of bounding box (default -MAXDOUBLE)
yh (Float, optional) – y position for corner of bounding box (default +MAXDOUBLE)
bloat (Float, optional) – Extend bounding box by this amount when search for mesh to include in region (default 1e-10)

devsim.add_2d_mesh_line(mesh, pos, ns, ps)

Add a mesh line to a 2D mesh

Parameters

mesh (str) – Mesh to add the line to
pos (str) – Position for the mesh point
ns (Float) – Spacing from this point in the negative direction
ps (Float) – Spacing from this point in the positive direction

devsim.add_2d_region(mesh, region, material, xl, xh, yl, yh, bloat)

Add a region to a 2D mesh

Parameters

mesh (str) – Mesh to add the region to
region (str) – Name for the region being created
material (str) – Material for the region being created
xl (Float, optional) – x position for corner of bounding box (default -MAXDOUBLE)
xh (Float, optional) – x position for corner of bounding box (default +MAXDOUBLE)
yl (Float, optional) – y position for corner of bounding box (default -MAXDOUBLE)
yh (Float, optional) – y position for corner of bounding box (default +MAXDOUBLE)
bloat (Float, optional) – Extend bounding box by this amount when search for mesh to include in region (default 1e-10)

devsim.add_gmsh_contact(gmsh_name, material, mesh, name, region)

Create a mesh to import a Gmsh mesh

Parameters

gmsh_name (str) – physical group name in the Gmsh file
material (str) – material for the contact being created
mesh (str) – name of the mesh being generated
name (str) – name of the contact begin created
region (str) – region that the contact is attached to

devsim.add_gmsh_interface(gmsh_name, mesh, name, region0, region1)

Create an interface for an imported Gmsh mesh

Parameters

gmsh_name (str) – physical group name in the Gmsh file
mesh (str) – name of the mesh being generated
name (str) – name of the interface begin created
region0 (str) – first region that the interface is attached to
region1 (str) – second region that the interface is attached to

devsim.add_gmsh_region(gmsh_name, mesh, region, material)

Create a region for an imported Gmsh mesh

Parameters

gmsh_name (str) – physical group name in the Gmsh file
mesh (str) – name of the mesh being generated
region (str) – name of the region begin created
material (str) – material for the region being created

devsim.create_1d_mesh(mesh)

Create a mesh to create a 1D device

Parameters: mesh (str) – name of the 1D mesh being created

devsim.create_2d_mesh(mesh)

Create a mesh to create a 2D device

Parameters: mesh (str) – name of the 2D mesh being created

devsim.create_contact_from_interface(device, region, interface, material, name)

Creates a contact on a device from an existing interface

Parameters

device (str) – The selected device
region (str) – The selected region
interface (str) – Interface on which to apply this command
material (str) – material for the contact being created
name (str) – name of the contact begin created

devsim.create_device(mesh, device)

Create a device from a mesh

Parameters

mesh (str) – name of the mesh being used to create a device
device (str) – name of the device being created

devsim.create_gmsh_mesh(mesh, file, coordinates, elements, physical_names)

Create a mesh to import a Gmsh mesh

Parameters

mesh (str) – name of the mesh being generated
file (str, optional) – name of the Gmsh mesh file being read into DEVSIM
coordinates (list, optional) – List of coordinate positions on mesh.
elements (list, optional) – List of elements on the mesh.
physical_names (list, optional) – List of names for each contact, interface, and region on mesh.

Notes

This file will import a Gmsh format mesh from a file. Alternatively, the mesh structure may be passed in as as arguments:

coordinates is a float list of positions in the mesh. Each coordinate adds an x, y, and z position so that the coordinate list length is 3 times the number of coordinates.

physical_names is a list of contact, interface, and region names. It is referenced by index by the elements list.

elements is a list of elements. Each element adds

Element Type (float)
- 0 node
- 1 edge
- 2 triangle
- 3 tetrahedron
Physical Index
- This indexes into the physical_names list.
Nodes
- Each node of the element indexes into the coordinates list.

devsim.create_interface_from_nodes(device, name, region0, region1, nodes0, nodes1)

Creates an interface from lists of nodes

Parameters

device (str) – The selected device
name (str) – name of the interface begin created
region0 (str) – first region that the interface is attached to
region1 (str) – second region that the interface is attached to
nodes0 (str) – list of nodes for the interface in the first region
nodes1 (str) – list of nodes for the interface in the second region

devsim.delete_device(device)

Delete a device and its parameters

Parameters: device (str) – name of the device being deleted

devsim.delete_mesh(mesh)

Delete a mesh so devices can no longer be instantiated from it.

Parameters: mesh (str) – Mesh to delete

devsim.finalize_mesh(mesh)

Finalize a mesh so no additional mesh specifications can be added and devices can be created.

Parameters: mesh (str) – Mesh to finalize

devsim.get_mesh_list(): Get list of meshes

devsim.load_devices(file)

Load devices from a DEVSIM file

Parameters: file (str) – name of the file to load the meshes from

devsim.write_devices(file, device, type)

Write a device to a file for visualization or restart

Parameters

file (str) – name of the file to write the meshes to
device (str, optional) – name of the device to write
type ({'devsim', 'devsim_data', 'floops', 'tecplot', 'vtk'}) – format to use

14.6. Model Commands

Commands for defining and evaluating models

devsim.contact_edge_model(device, contact, name, equation, display_type)

Create an edge model evaluated at a contact

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
name (str) – Name of the contact edge model being created
equation (str) – Equation used to describe the contact edge model being created
display_type ({'vector', 'nodisplay', 'scalar'}) – Option for output display in graphical viewer

devsim.contact_node_model(device, contact, name, equation, display_type)

Create an node model evaluated at a contact

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
name (str) – Name of the contact node model being created
equation (str) – Equation used to describe the contact node model being created
display_type ({'scalar', 'nodisplay'}) – Option for output display in graphical viewer

devsim.cylindrical_edge_couple(device, region)

This command creates the EdgeCouple model for 2D cylindrical simulation

Parameters

device (str) – The selected device
region (str) – The selected region

Notes

This model is only available in 2D. The created variables are

ElementCylindricalEdgeCouple (Element Edge Model)
CylindricalEdgeCouple (Edge Model)

The devsim.set_parameter() must be used to set

raxis_variable, the variable (x or y) which is the radial axis variable in the cylindrical coordinate system
raxis_zero, the location of the z axis for the radial axis variable

devsim.cylindrical_node_volume(device, region)

This command creates the NodeVolume model for 2D cylindrical simulation

Parameters

device (str) – The selected device
region (str) – The selected region

Notes

This model is only available in 2D. The created variables are

ElementCylindricalNodeVolume@en0 (Element Edge Model)
ElementCylindricalNodeVolume@en1 (Element Edge Model)
CylindricalEdgeNodeVolume@n0 (Edge Model)
CylindricalEdgeNodeVolume@n1 (Edge Model)
CylindricalNodeVolume (Node Model)

The ElementCylindricalNodeVolume@en0 and ElementCylindricalNodeVolume@en1 represent the node volume at each end of the element edge.

The devsim.set_parameter() must be used to set

raxis_variable, the variable (x or y) which is the radial axis variable in the cylindrical coordinate system
raxis_zero, the location of the z axis for the radial axis variable

devsim.cylindrical_surface_area(device, region)

This command creates the SurfaceArea model for 2D cylindrical simulation

Parameters

device (str) – The selected device
region (str) – The selected region

Notes

This model is only available in 2D. The created variables are

CylindricalSurfaceArea (Node Model)

and is the cylindrical surface area along each contact and interface node in the device region.

The devsim.set_parameter() must be used to set

raxis_variable, the variable (x or y) which is the radial axis variable in the cylindrical coordinate system
raxis_zero, the location of the z axis for the radial axis variable

devsim.debug_triangle_models(device, region)

Debugging command used in the development of DEVSIM and used in regressions.

Parameters

device (str) – The selected device
region (str) – The selected region

devsim.delete_edge_model(device, region, name)

Deletes an edge model from a region

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the edge model being deleted

devsim.delete_element_model(device, region, name)

Deletes a element model from a region

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model being deleted

devsim.delete_interface_model(device, interface, name)

Deletes an interface model from an interface

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
name (str) – Name of the interface model being deleted

devsim.delete_node_model(device, region, name)

Deletes a node model from a region

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model being deleted

devsim.edge_average_model(device, region, node_model, edge_model, derivative, average_type)

Creates an edge model based on the node model values

Parameters

device (str) – The selected device
region (str) – The selected region
node_model (str) – The node model from which we are creating the edge model. If derivative is specified, the edge model is created from nodeModel:derivativeModel
edge_model (str) – The edge model name being created. If derivative is specified, the edge models created are edgeModel:derivativeModel@n0 edgeModel:derivativeModel@n1, which are the derivatives with respect to the derivative model on each side of the edge
derivative (str, optional) – The node model of the variable for which the derivative is being taken. The node model nodeModel:derivativeModel is used to create the resulting edge models.
average_type ({'arithmetic', 'geometric', 'gradient', 'negative_gradient'}) – The node models on both sides of the edge are averaged together to create one of the following types of averages.

Notes

For a node model, creates 2 edge models referring to the node model value at both ends of the edge. For example, to calculate electric field:

devsim.edge_average_model(device=device, region=region, node_model=”Potential”, edge_model=”ElecticField”, average_type=”negative_gradient”)

and the derivatives ElectricField:Potential@n0 and ElectricField:Potential@n1 are then created from

devsim.edge_average_model(device=device, region=region, node_model=”Potential”, edge_model=”ElecticField”, average_type=”negative_gradient”, derivative=”Potential”)

devsim.edge_from_node_model(device, region, node_model)

For a node model, creates an 2 edge models referring to the node model value at both ends of the edge.

Parameters

device (str) – The selected device
region (str) – The selected region
node_model (str) – The node model from which we are creating the edge model

Notes

For example, to calculate electric field:

devsim.edge_from_node_model(device=device, region=region, node_model=”Potential”)

devsim.edge_model(device, region, name, equation, display_type)

Creates an edge model based on an equation

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the edge model being created
equation (str) – Equation used to describe the edge model being created
display_type ({'scalar', 'nodisplay', 'vector'}) – Option for output display in graphical viewer

Notes

The vector option uses an averaging scheme for the edge values projected in the direction of each edge. For a given model, model, the generated components in the visualization files is:

model_x_onNode
model_y_onNode
model_z_onNode (3D)

This averaging scheme does not produce accurate results, and it is recommended to use the devsim.element_from_edge_model() to create components better suited for visualization. See Visualization for more information about creating data files for external visualization programs.

devsim.edge_solution(device, region, name)

Create node model whose values are set.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the solution being created

devsim.element_from_edge_model(device, region, edge_model, derivative)

Creates element edge models from an edge model

Parameters

device (str) – The selected device
region (str) – The selected region
edge_model (str) – The edge model from which we are creating the element model
derivative (str, optional) – The variable we are taking with respect to edge_model

Notes

For an edge model emodel, creates an element models referring to the directional components on each edge of the element:

emodel_x
emodel_y

If the derivative variable option is specified, the emodel@n0 and emodel@n1 are used to create:

emodel_x:variable@en0
emodel_y:variable@en0
emodel_x:variable@en1
emodel_y:variable@en1
emodel_x:variable@en2
emodel_y:variable@en2

in 2D for each node on a triangular element. and

emodel_x:variable@en0
emodel_y:variable@en0
emodel_z:variable@en0
emodel_x:variable@en1
emodel_y:variable@en1
emodel_z:variable@en1
emodel_x:variable@en2
emodel_y:variable@en2
emodel_z:variable@en2
emodel_x:variable@en3
emodel_y:variable@en3
emodel_z:variable@en3

in 3D for each node on a tetrahedral element.

The suffix en0 refers to the first node on the edge of the element and en1 refers to the second node. en2 and en3 specifies the derivatives with respect the variable at the nodes opposite the edges on the element being considered.

devsim.element_from_node_model(device, region, node_model)

Creates element edge models from a node model

Parameters

device (str) – The selected device
region (str) – The selected region
node_model (str) – The node model from which we are creating the edge model

Notes

This command creates an element edge model from a node model so that each corner of the element is represented. A node model, nmodel, would be be accessible as

nmodel@en0
nmodel@en1
nmodel@en2
nmodel@en3 (3D)

where en0, and en1 refers to the nodes on the element’s edge. In 2D, en2 refers to the node on the triangle node opposite the edge. In 3D, en2 and en3 refers to the nodes on the nodes off the element edge on the tetrahedral element.

devsim.element_model(device, region, name, equation, display_type)

Create a model evaluated on element edges.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the element edge model being created
equation (str) – Equation used to describe the element edge model being created
display_type ({'scalar', 'nodisplay'}) – Option for output display in graphical viewer

devsim.element_pair_from_edge_model(device, region, edge_model, derivative)

Creates element edge models from an edge model

Parameters

device (str) – The selected device
region (str) – The selected region
edge_model (str) – The edge model from which we are creating the element model
derivative (str, optional) – The variable we are taking with respect to edge_model

Notes

For an edge model emodel, creates an element models referring to the directional components on each edge of the element:

emodel_node0_x
emodel_node0_y
emodel_node1_x
emodel_node1_y

If the derivative variable option is specified, the emodel@n0 and emodel@n1 are used to create:

emodel_node0_x:variable@en0
emodel_node0_y:variable@en0
emodel_node0_x:variable@en1
emodel_node0_y:variable@en1
emodel_node0_x:variable@en2
emodel_node0_y:variable@en2
emodel_node1_x:variable@en0
emodel_node1_y:variable@en0
emodel_node1_x:variable@en1
emodel_node1_y:variable@en1
emodel_node1_x:variable@en2
emodel_node1_y:variable@en2

in 2D for each node on a triangular element. and

emodel_node0_x:variable@en0
emodel_node0_y:variable@en0
emodel_node0_z:variable@en0
emodel_node0_x:variable@en1
emodel_node0_y:variable@en1
emodel_node0_z:variable@en1
emodel_node0_x:variable@en2
emodel_node0_y:variable@en2
emodel_node0_z:variable@en2
emodel_node0_x:variable@en3
emodel_node0_y:variable@en3
emodel_node0_z:variable@en3
emodel_node1_x:variable@en0
emodel_node1_y:variable@en0
emodel_node1_z:variable@en0
emodel_node1_x:variable@en1
emodel_node1_y:variable@en1
emodel_node1_z:variable@en1
emodel_node1_x:variable@en2
emodel_node1_y:variable@en2
emodel_node1_z:variable@en2
emodel_node1_x:variable@en3
emodel_node1_y:variable@en3
emodel_node1_z:variable@en3

in 3D for each node on a tetrahedral element.

The label node0 and node1 refer to the node on the edge for which the element field average was performed. For example, node0 signifies that all edges connected to node0 where used to calculate the element field.

The suffix en0 refers to the first node on the edge of the element and en1 refers to the second node. en2 and en3 specifies the derivatives with respect the variable at the nodes opposite the edges on the element being considered.

devsim.element_solution(device, region, name)

Create node model whose values are set.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the solution being created

devsim.get_edge_model_list(device, region)

Returns a list of the edge models on the device region

Parameters

device (str) – The selected device
region (str) – The selected region

devsim.get_edge_model_values(device, region, name)

Get the edge model values calculated at each edge.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the edge model values being returned as a list

devsim.get_element_model_list(device, region)

Returns a list of the element edge models on the device region

Parameters

device (str) – The selected device
region (str) – The selected region

devsim.get_element_model_values(device, region, name)

Get element model values at each element edge

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the element edge model values being returned as a list

devsim.get_interface_model_list(device, interface)

Returns a list of the interface models on the interface

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command

devsim.get_interface_model_values(device, interface, name)

Gets interface model values evaluated at each interface node.

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
name (str) – Name of the interface model values being returned as a list

devsim.get_node_model_list(device, region)

Returns a list of the node models on the device region

Parameters

device (str) – The selected device
region (str) – The selected region

devsim.get_node_model_values(device, region, name)

Get node model values evaluated at each node in a region.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model values being returned as a list

devsim.interface_model(device, interface, equation)

Create an interface model from an equation.

Parameters

device (str) – The selected device
interface (str) – Interface on which to apply this command
equation (str) – Equation used to describe the interface node model being created

devsim.interface_normal_model(device, region, interface)

Creates edge models whose components are based on direction and distance to an interface

Parameters

device (str) – The selected device
region (str) – The selected region
interface (str) – Interface on which to apply this command

Notes

This model creates the following edge models:

iname_distance
iname_normal_x (2D and 3D)
iname_normal_y (2D and 3D)
iname_normal_z (3D only)

where iname is the name of the interface. The normals are of the closest node on the interface. The sign is toward the interface.

devsim.node_model(device, region, name, equation, display_type)

Create a node model from an equation.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model being created
equation (str) – Equation used to describe the node model being created
display_type ({'scalar', 'nodisplay'}) – Option for output display in graphical viewer

devsim.node_solution(device, region, name)

Create node model whose values are set.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the solution being created

devsim.print_edge_values(device, region, name)

Print edge values for debugging.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the edge model values being printed to the screen

devsim.print_element_values(device, region, name)

Print element values for debugging.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the element edge model values being printed to the screen

devsim.print_node_values(device, region, name)

Print node values for debugging.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model values being printed to the screen

devsim.register_function(name, nargs, procedure)

This command is used to register a new Python procedure for evaluation by SYMDIFF.

Parameters

name (str) – Name of the function
nargs (str) – Number of arguments to the function
procedure (str) – The procedure to be called

devsim.set_edge_values(device, region, name, init_from, values)

Set edge model values from another edge model, or a list of values.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the edge model being initialized
init_from (str, optional) – Node model we are using to initialize the edge solution
values (list, optional) – List of values for each edge in the region.

devsim.set_element_values(device, region, name, init_from, values)

Set element model values from another element model, or a list of values.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the element model being initialized
init_from (str, optional) – Node model we are using to initialize the element solution
values (list, optional) – List of values for each element in the region.

devsim.set_node_value(device, region, name, index, value)

A uniform value is used if index is not specified. Note that equation based node models will lose this value if their equation is recalculated.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model being whose value is being set
index (int) – Index of node being set
value (Float) – Value of node being set

devsim.set_node_values(device, region, name, init_from, values)

Set node model values from another node model, or a list of values.

Parameters

device (str) – The selected device
region (str) – The selected region
name (str) – Name of the node model being initialized
init_from (str, optional) – Node model we are using to initialize the node solution
values (list, optional) – List of values for each node in the region.

devsim.symdiff(expr)

This command returns an expression. All strings are treated as independent variables. It is primarily used for defining new functions to the parser.

Parameters: expr (str) – Expression to send to SYMDIFF

devsim.vector_element_model(device, region, element_model)

Create vector components from an element edge model

Parameters

device (str) – The selected device
region (str) – The selected region
element_model (str) – The element model for which we are calculating the vector components

Notes

This command creates element edge models from an element model which represent the vector components on the element edge. An element model, emodel, would then have

emodel_x
emodel_y
emodel_z (3D only)

The primary use of these components are for visualization.

devsim.vector_gradient(device, region, node_model, calc_type)

Creates the vector gradient for noise analysis

Parameters

device (str) – The selected device
region (str) – The selected region
node_model (str) – The node model from which we are creating the edge model
calc_type ({'default', 'avoidzero'}) – The node model from which we are creating the edge model

Notes

Used for noise analysis. The avoidzero option is important for noise analysis, since a node model value of zero is not physical for some contact and interface boundary conditions. For a given node model, model, a node model is created in each direction:

model_gradx (1D)
model_grady (2D and 3D)
model_gradz (3D)

It is important not to use these models for simulation, since DEVSIM, does not have a way of evaluating the derivatives of these models. The models can be used for integrating the impedance field, and other postprocessing. The devsim.element_from_edge_model() command can be used to create gradients for use in a simulation.

14.7. Solver Commands

Commands for simulation

devsim.get_contact_charge(device, contact, equation)

Get charge at the contact

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
equation (str) – Name of the contact equation from which we are retrieving the charge

devsim.get_contact_current(device, contact, equation)

Get current at the contact

Parameters

device (str) – The selected device
contact (str) – Contact on which to apply this command
equation (str) – Name of the contact equation from which we are retrieving the current

devsim.get_matrix_and_rhs(format)

Returns matrices and rhs vectors.

Parameters: format ({'csc', 'csr'} required) – Option for returned matrix format.

devsim.set_initial_condition(static_rhs, dynamic_rhs)

Sets the initial condition for subsequent transient solver steps.

Parameters

static_rhs (list, optional) – List of double values for non time-displacement terms in right hand side.
dynamic_rhs (list, optional) – List of double values for time-displacement terms in right hand side.

devsim.solve(type, solver_type, absolute_error, relative_error, maximum_error, charge_error, gamma, tdelta, maximum_iterations, maximum_divergence, frequency, output_node, info, symbolic_iteration_limit)

Call the solver. A small-signal AC source is set with the circuit voltage source.

Parameters

type ({'dc', 'ac', 'noise', 'transient_dc', 'transient_bdf1', 'transient_bdf2', 'transient_tr'} required) – type of solve being performed
solver_type ({'direct', 'iterative'} required) – Linear solver type
absolute_error (Float, optional) – Required update norm in the solve (default 0.0)
relative_error (Float, optional) – Required relative update in the solve (default 0.0)
maximum_error (Float, optional) – Maximum absolute error before solve stops (default MAXDOUBLE)
charge_error (Float, optional) – Relative error between projected and solved charge during transient simulation (default 0.0)
gamma (Float, optional) – Scaling factor for transient time step (default 1.0)
tdelta (Float, optional) – time step (default 0.0)
maximum_iterations (int, optional) – Maximum number of iterations in the DC solve (default 20)
maximum_divergence (int, optional) – Maximum number of diverging iterations during solve (default 20)
frequency (Float, optional) – Frequency for small-signal AC simulation (default 0.0)
output_node (str, optional) – Output circuit node for noise simulation
info (bool, optional) – Solve command return convergence information (default False)
symbolic_iteration_limit (int, optional) – Reuse symbolic matrix factorization after this number of iterations (default 1)