"""
CIE Constants
=============

Define *CIE* constants.

References
----------
-   :cite:`Wyszecki2000s` : Wyszecki, Günther, & Stiles, W. S. (2000).
    Standard Photometric Observers. In Color Science: Concepts and Methods,
    Quantitative Data and Formulae (pp. 256-259,395). Wiley.
    ISBN:978-0-471-39918-6
"""

from colour.utilities.documentation import DocstringFloat, is_documentation_building

__author__ = "Colour Developers"
__copyright__ = "Copyright 2013 Colour Developers"
__license__ = "BSD-3-Clause - https://opensource.org/licenses/BSD-3-Clause"
__maintainer__ = "Colour Developers"
__email__ = "colour-developers@colour-science.org"
__status__ = "Production"

__all__ = [
    "CONSTANT_K_M",
    "CONSTANT_KP_M",
]

CONSTANT_K_M: float = 683
if is_documentation_building():  # pragma: no cover
    CONSTANT_K_M = DocstringFloat(CONSTANT_K_M)
    CONSTANT_K_M.__doc__ = """
Rounded maximum photopic luminous efficiency :math:`K_m` value in
:math:`lm\\cdot W^{-1}`.

Notes
-----
-   To be adequate for all practical applications the :math:`K_m` value has
    been rounded from the original 683.002 value.

References
----------
:cite:`Wyszecki2000s`
"""

CONSTANT_KP_M: float = 1700
if is_documentation_building():  # pragma: no cover
    CONSTANT_KP_M = DocstringFloat(CONSTANT_KP_M)
    CONSTANT_KP_M.__doc__ = """
Rounded maximum scotopic luminous efficiency :math:`K^{\\prime}_m` value in
:math:`lm\\cdot W^{-1}`.

Notes
-----
-   To be adequate for all practical applications the :math:`K^{\\prime}_m`
    value has been rounded from the original 1700.06 value.

References
----------
:cite:`Wyszecki2000s`
"""