pyissm.model.classes.stressbalance

class pyissm.model.classes.stressbalance(other=None)

Bases: manage_state

Stress balance solution parameters class for ISSM.

This class encapsulates parameters for configuring stress balance simulations in the ISSM (Ice Sheet System Model) framework. It controls velocity constraints, convergence criteria, numerical methods, and other parameters for solving the momentum balance equations in ice sheet dynamics.

Parameters:: other (any, optional) – Any other class object that contains common fields to inherit from. If values in other differ from default values, they will override the default values.

spcvx

Velocity constraints in x-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvy

Velocity constraints in y-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvx_base

Base velocity constraints in x-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvy_base

Base velocity constraints in y-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvx_shear

Shear velocity constraints in x-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvy_shear

Shear velocity constraints in y-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

spcvz

Velocity constraints in z-direction (NaN means no constraint) [m/yr].

Type:: ndarray, default=nan

restol

Mechanical equilibrium residual convergence criterion.

Type:: float, default=1e-4

reltol

Velocity relative convergence criterion (NaN: not applied).

Type:: float, default=0.01

abstol

Velocity absolute convergence criterion (NaN: not applied).

Type:: float, default=10

ishydrologylayer

Is hydrology layer enabled.

Type:: int, default=0

isnewton

Numerical method: 0=Picard’s fixed point, 1=Newton’s method, 2=hybrid.

Type:: int, default=0

FSreconditioning

Full-Stokes reconditioning parameter.

Type:: float, default=1e13

maxiter

Maximum number of nonlinear iterations.

Type:: int, default=100

shelf_dampening

Shelf dampening parameter.

Type:: float, default=0

vertex_pairing

Vertex pairing parameter.

Type:: float, default=nan

penalty_factor

Penalty factor for constraint enforcement.

Type:: float, default=3

rift_penalty_lock

Rift penalty lock parameter.

Type:: float, default=10

rift_penalty_threshold

Rift penalty threshold parameter.

Type:: float, default=0

referential

Referential parameter.

Type:: float, default=nan

loadingforce

Loading force parameter.

Type:: float, default=nan

requested_outputs

Additional outputs requested.

Type:: list, default=[‘default’]

__init__(self, other=None): Initializes the stressbalance parameters, optionally inheriting from another instance.

__repr__(self): Returns a detailed string representation of the stressbalance parameters.

__str__(self): Returns a short string identifying the class.

process_outputs(self, md=None, return_default_outputs=False): Process requested outputs, expanding ‘default’ to appropriate outputs.

marshall_class(self, fid, prefix, md=None): Marshall parameters to a binary file

Examples

md.stressbalance = pyissm.model.classes.stressbalance() md.stressbalance.restol = 1e-5 md.stressbalance.isnewton = 1 md.stressbalance.maxiter = 200

__init__(other=None)

Initialize the instance with optional field inheritance.

Parameters:: other (object, optional) – Another instance to inherit field values from. If provided, any fields in the current instance that differ from the default values and exist in ‘other’ will be replaced with the values from ‘other’.

Notes

The inheritance process:

Iterates through all attributes of the current instance

Checks if the same attribute exists in the ‘other’ instance

Compares field values using _fields_equal()

If different, replaces the current value with the ‘other’ value

This enables the common ISSM pattern where classes can inherit configurations from existing instances while maintaining their default values for unspecified fields.

Methods

`__init__`([other])	Initialize the instance with optional field inheritance.
`check_consistency`(md, solution, analyses)	Check consistency of the [stressbalance.stressbalance] parameters.
`issm_enum_string`()	Default ISSM C++ enum string used during marshalling.
`marshall_class`(fid, prefix[, md])	Marshall [stressbalance.stressbalance] parameters to a binary file.

check_consistency(md, solution, analyses)

Check consistency of the [stressbalance.stressbalance] parameters.

Parameters:

md (pyissm.model.Model) – The model object to check.
solution (str) – The solution name to check.
analyses (list of str) – List of analyses to check consistency for.

Returns:

md – The model object with any consistency errors noted.

Return type:

pyissm.model.Model

marshall_class(fid, prefix, md=None)

Marshall [stressbalance.stressbalance] parameters to a binary file.

Parameters:

fid (file object) – The file object to write the binary data to.
prefix (str) – Prefix string used for data identification in the binary file.
md (ISSM model object, optional.) – ISSM model object needed in some cases.

Return type:

None