PhysicalConstantsContext

class qcelemental.PhysicalConstantsContext(context='CODATA2014')[source]

Bases: object

CODATA physical constants set from NIST.

Parameters:: context (str) – {‘CODATA2014’, ‘CODATA2018’} Origin of loaded data.

doi

The DOI of the current context.

Type:: str

name

The name of the context (‘CODATA2014’)

Type:: str

pc

Each physical constant is an entry in pc, where key is the lowercased string of the NIST name (or any alias) and the value is a Datum object with lbl the exact NIST name string, units, data value as Decimal object, and any uncertainty in the comment field.

Type:: Dict[str, Datum]

raw_codata

A dictionary representation of the raw context data.

Type:: Dict[str, Any]

year

The year the context was created.

Type:: int

Attributes Summary

ureg

Returns the internal Pint units registry.

Methods Summary

`Quantity`(data)	Returns a Pint Quantity.
`conversion_factor`(base_unit, conv_unit)	Provides the conversion factor from one unit to another.
`get`(physical_constant[, return_tuple])	Access a physical constant, physical_constant.
`string_representation`()	Print name, value, and units of all physical constants.

Attributes Documentation

ureg

Returns the internal Pint units registry.

Returns:: The pint context
Return type:: UnitRegistry

Methods Documentation

Quantity(data)[source]

Returns a Pint Quantity.

Return type:: Quantity
Parameters:: data (str) –

conversion_factor(base_unit, conv_unit)[source]

Provides the conversion factor from one unit to another.

The conversion factor is based on the current contexts CODATA.

Parameters:

base_unit (Union[str, Quantity]) – The original units
conv_unit (Union[str, Quantity]) – The units to convert to

Return type:

float

Examples

>>> conversion_factor("meter", "picometer")
1e-12

>>> conversion_factor("feet", "meter")
0.30479999999999996

>>> conversion_factor(10 * ureg.feet, "meter")
3.0479999999999996

Returns:

The requested conversion factor

Return type:

float

Parameters:

base_unit (Union[str, Quantity]) –
conv_unit (Union[str, Quantity]) –

get(physical_constant, return_tuple=False)[source]

Access a physical constant, physical_constant.

Parameters:

physical_constant (str) – Case-insensitive string of physical constant with NIST name.
return_tuple (bool) – See below.

Returns:

When return_tuple=False, value of physical constant. When return_tuple=True, Datum with units, description, uncertainty, and value of physical constant as Decimal.

Return type:

Union[float, Datum]

string_representation()[source]

Print name, value, and units of all physical constants.

Return type:: str