pyissm.model.classes.constants

class pyissm.model.classes.constants(other=None)

Bases: manage_state

Physical constants class for ISSM.

This class contains fundamental physical constants used in the ISSM framework. It provides standardized values for gravitational acceleration, Earth’s rotation, time conversions, and other physical constants required for ice sheet modeling calculations.

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.

g

Gravitational acceleration [m/s^2].

Type:

float, default=9.81

omega

Angular velocity of Earth [rad/s].

Type:

float, default=7.292e-5

yts

Number of seconds in a year [s/yr] (365.0 * 24.0 * 3600.0).

Type:

float, default=31536000.0

referencetemperature

Reference temperature used in the enthalpy model [K].

Type:

float, default=223.15

gravitational_constant

Newtonian constant of gravitation [m^3/kg/s^2].

Type:

float, default=6.67259e-11

Examples

>>> md.constants = pyissm.model.classes.constants()
>>> md.constants.g = 9.81
>>> md.constants.yts = 365.25 * 24.0 * 3600.0
__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:

  1. Iterates through all attributes of the current instance

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

  3. Compares field values using _fields_equal()

  4. 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 [constants] parameters.

issm_enum_string()

Default ISSM C++ enum string used during marshalling.

marshall_class(fid, prefix[, md])

Marshall [constants.constants] parameters to a binary file.
check_consistency(md, solution, analyses)

Check consistency of the [constants] 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 [constants.constants] 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 (pyissm.model.Model, optional) – ISSM model object needed in some cases.

Return type:

None