InputUnitsMap

class PlasmaCalcs.units.input_units.InputUnitsMap(mapping=None, *, maps_to='si')

Bases: object

directly map “input units” conversion factors to particular variables.

Especially useful if “input units” is not a self-consistent unit system.

Call instance to get conversion factor, like:

self(var, u) –> conversion factor from “input units” to u.units for var.

where u is a UnitsManager object.

mapping: None or dict of {var: (ustr, var_to_si)}

tells how to map each var into the self-consistent units system maps_to

None –> no conversion factor (equivalent to all factors == 1);

this is the “trivial” mapping.

dict –> ustr is string to pass to a UnitsManager;

var_to_si is conversion factor from “input units” to SI units,

where original units is the original unit system being converted from.

Example mapping:

{‘B’: (‘b_field’, 1e-9), # for ‘B’ with input_units [nT]

‘n’: (‘number_density’, 1e6), # for ‘n’ with input_units [1/cm^3]

‘P’: (‘pressure’, 1e-9), # for ‘P’ with input_units [nPa]

‘J’: (‘current_density’, 1e-9), # for ‘J’ with input_units [nA/m^2]

‘u’: (‘velocity’, 1e-3)} # for ‘u’ with input_units [km/s]

maps_to: ‘si’, ‘raw’, or other str

the self-consistent unit system mapped to by self.mapping.

must be in u.known_systems during self.__call__.

Example:

for mapping above, which provides factors to go from input units to ‘si’,

it makes sense to use maps_to=’si’.

Example:

if “input units” is just ‘raw’ units from self.u, use maps_to=’raw’.

(In this case, the InputUnitsMap machinery isn’t really necessary…

but it is convenient to be able reproduce this case just by

changing the args here, rather than many if/else checks in other places.)

Methods

__call__(var, u)

return conversion factor from "input_units" to u.units for var.

__call__(var, u)

return conversion factor from “input_units” to u.units for var.