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r""" 

================================== 

Constants (:mod:`scipy.constants`) 

================================== 

 

.. currentmodule:: scipy.constants 

 

Physical and mathematical constants and units. 

 

 

Mathematical constants 

====================== 

 

================ ================================================================= 

``pi`` Pi 

``golden`` Golden ratio 

``golden_ratio`` Golden ratio 

================ ================================================================= 

 

 

Physical constants 

================== 

 

=========================== ================================================================= 

``c`` speed of light in vacuum 

``speed_of_light`` speed of light in vacuum 

``mu_0`` the magnetic constant :math:`\mu_0` 

``epsilon_0`` the electric constant (vacuum permittivity), :math:`\epsilon_0` 

``h`` the Planck constant :math:`h` 

``Planck`` the Planck constant :math:`h` 

``hbar`` :math:`\hbar = h/(2\pi)` 

``G`` Newtonian constant of gravitation 

``gravitational_constant`` Newtonian constant of gravitation 

``g`` standard acceleration of gravity 

``e`` elementary charge 

``elementary_charge`` elementary charge 

``R`` molar gas constant 

``gas_constant`` molar gas constant 

``alpha`` fine-structure constant 

``fine_structure`` fine-structure constant 

``N_A`` Avogadro constant 

``Avogadro`` Avogadro constant 

``k`` Boltzmann constant 

``Boltzmann`` Boltzmann constant 

``sigma`` Stefan-Boltzmann constant :math:`\sigma` 

``Stefan_Boltzmann`` Stefan-Boltzmann constant :math:`\sigma` 

``Wien`` Wien displacement law constant 

``Rydberg`` Rydberg constant 

``m_e`` electron mass 

``electron_mass`` electron mass 

``m_p`` proton mass 

``proton_mass`` proton mass 

``m_n`` neutron mass 

``neutron_mass`` neutron mass 

=========================== ================================================================= 

 

 

Constants database 

------------------ 

 

In addition to the above variables, :mod:`scipy.constants` also contains the 

2018 CODATA recommended values [CODATA2018]_ database containing more physical 

constants. 

 

.. autosummary:: 

:toctree: generated/ 

 

value -- Value in physical_constants indexed by key 

unit -- Unit in physical_constants indexed by key 

precision -- Relative precision in physical_constants indexed by key 

find -- Return list of physical_constant keys with a given string 

ConstantWarning -- Constant sought not in newest CODATA data set 

 

.. data:: physical_constants 

 

Dictionary of physical constants, of the format 

``physical_constants[name] = (value, unit, uncertainty)``. 

 

Available constants: 

 

====================================================================== ==== 

%(constant_names)s 

====================================================================== ==== 

 

 

Units 

===== 

 

SI prefixes 

----------- 

 

============ ================================================================= 

``yotta`` :math:`10^{24}` 

``zetta`` :math:`10^{21}` 

``exa`` :math:`10^{18}` 

``peta`` :math:`10^{15}` 

``tera`` :math:`10^{12}` 

``giga`` :math:`10^{9}` 

``mega`` :math:`10^{6}` 

``kilo`` :math:`10^{3}` 

``hecto`` :math:`10^{2}` 

``deka`` :math:`10^{1}` 

``deci`` :math:`10^{-1}` 

``centi`` :math:`10^{-2}` 

``milli`` :math:`10^{-3}` 

``micro`` :math:`10^{-6}` 

``nano`` :math:`10^{-9}` 

``pico`` :math:`10^{-12}` 

``femto`` :math:`10^{-15}` 

``atto`` :math:`10^{-18}` 

``zepto`` :math:`10^{-21}` 

============ ================================================================= 

 

Binary prefixes 

--------------- 

 

============ ================================================================= 

``kibi`` :math:`2^{10}` 

``mebi`` :math:`2^{20}` 

``gibi`` :math:`2^{30}` 

``tebi`` :math:`2^{40}` 

``pebi`` :math:`2^{50}` 

``exbi`` :math:`2^{60}` 

``zebi`` :math:`2^{70}` 

``yobi`` :math:`2^{80}` 

============ ================================================================= 

 

Mass 

---- 

 

================= ============================================================ 

``gram`` :math:`10^{-3}` kg 

``metric_ton`` :math:`10^{3}` kg 

``grain`` one grain in kg 

``lb`` one pound (avoirdupous) in kg 

``pound`` one pound (avoirdupous) in kg 

``blob`` one inch version of a slug in kg (added in 1.0.0) 

``slinch`` one inch version of a slug in kg (added in 1.0.0) 

``slug`` one slug in kg (added in 1.0.0) 

``oz`` one ounce in kg 

``ounce`` one ounce in kg 

``stone`` one stone in kg 

``grain`` one grain in kg 

``long_ton`` one long ton in kg 

``short_ton`` one short ton in kg 

``troy_ounce`` one Troy ounce in kg 

``troy_pound`` one Troy pound in kg 

``carat`` one carat in kg 

``m_u`` atomic mass constant (in kg) 

``u`` atomic mass constant (in kg) 

``atomic_mass`` atomic mass constant (in kg) 

================= ============================================================ 

 

Angle 

----- 

 

================= ============================================================ 

``degree`` degree in radians 

``arcmin`` arc minute in radians 

``arcminute`` arc minute in radians 

``arcsec`` arc second in radians 

``arcsecond`` arc second in radians 

================= ============================================================ 

 

 

Time 

---- 

 

================= ============================================================ 

``minute`` one minute in seconds 

``hour`` one hour in seconds 

``day`` one day in seconds 

``week`` one week in seconds 

``year`` one year (365 days) in seconds 

``Julian_year`` one Julian year (365.25 days) in seconds 

================= ============================================================ 

 

 

Length 

------ 

 

===================== ============================================================ 

``inch`` one inch in meters 

``foot`` one foot in meters 

``yard`` one yard in meters 

``mile`` one mile in meters 

``mil`` one mil in meters 

``pt`` one point in meters 

``point`` one point in meters 

``survey_foot`` one survey foot in meters 

``survey_mile`` one survey mile in meters 

``nautical_mile`` one nautical mile in meters 

``fermi`` one Fermi in meters 

``angstrom`` one Angstrom in meters 

``micron`` one micron in meters 

``au`` one astronomical unit in meters 

``astronomical_unit`` one astronomical unit in meters 

``light_year`` one light year in meters 

``parsec`` one parsec in meters 

===================== ============================================================ 

 

Pressure 

-------- 

 

================= ============================================================ 

``atm`` standard atmosphere in pascals 

``atmosphere`` standard atmosphere in pascals 

``bar`` one bar in pascals 

``torr`` one torr (mmHg) in pascals 

``mmHg`` one torr (mmHg) in pascals 

``psi`` one psi in pascals 

================= ============================================================ 

 

Area 

---- 

 

================= ============================================================ 

``hectare`` one hectare in square meters 

``acre`` one acre in square meters 

================= ============================================================ 

 

 

Volume 

------ 

 

=================== ======================================================== 

``liter`` one liter in cubic meters 

``litre`` one liter in cubic meters 

``gallon`` one gallon (US) in cubic meters 

``gallon_US`` one gallon (US) in cubic meters 

``gallon_imp`` one gallon (UK) in cubic meters 

``fluid_ounce`` one fluid ounce (US) in cubic meters 

``fluid_ounce_US`` one fluid ounce (US) in cubic meters 

``fluid_ounce_imp`` one fluid ounce (UK) in cubic meters 

``bbl`` one barrel in cubic meters 

``barrel`` one barrel in cubic meters 

=================== ======================================================== 

 

Speed 

----- 

 

================== ========================================================== 

``kmh`` kilometers per hour in meters per second 

``mph`` miles per hour in meters per second 

``mach`` one Mach (approx., at 15 C, 1 atm) in meters per second 

``speed_of_sound`` one Mach (approx., at 15 C, 1 atm) in meters per second 

``knot`` one knot in meters per second 

================== ========================================================== 

 

 

Temperature 

----------- 

 

===================== ======================================================= 

``zero_Celsius`` zero of Celsius scale in Kelvin 

``degree_Fahrenheit`` one Fahrenheit (only differences) in Kelvins 

===================== ======================================================= 

 

.. autosummary:: 

:toctree: generated/ 

 

convert_temperature 

 

Energy 

------ 

 

==================== ======================================================= 

``eV`` one electron volt in Joules 

``electron_volt`` one electron volt in Joules 

``calorie`` one calorie (thermochemical) in Joules 

``calorie_th`` one calorie (thermochemical) in Joules 

``calorie_IT`` one calorie (International Steam Table calorie, 1956) in Joules 

``erg`` one erg in Joules 

``Btu`` one British thermal unit (International Steam Table) in Joules 

``Btu_IT`` one British thermal unit (International Steam Table) in Joules 

``Btu_th`` one British thermal unit (thermochemical) in Joules 

``ton_TNT`` one ton of TNT in Joules 

==================== ======================================================= 

 

Power 

----- 

 

==================== ======================================================= 

``hp`` one horsepower in watts 

``horsepower`` one horsepower in watts 

==================== ======================================================= 

 

Force 

----- 

 

==================== ======================================================= 

``dyn`` one dyne in newtons 

``dyne`` one dyne in newtons 

``lbf`` one pound force in newtons 

``pound_force`` one pound force in newtons 

``kgf`` one kilogram force in newtons 

``kilogram_force`` one kilogram force in newtons 

==================== ======================================================= 

 

Optics 

------ 

 

.. autosummary:: 

:toctree: generated/ 

 

lambda2nu 

nu2lambda 

 

References 

========== 

 

.. [CODATA2018] CODATA Recommended Values of the Fundamental 

Physical Constants 2018. 

 

https://physics.nist.gov/cuu/Constants/ 

 

""" 

# Modules contributed by BasSw (wegwerp@gmail.com) 

from .codata import * 

from .constants import * 

from .codata import _obsolete_constants 

 

_constant_names = [(_k.lower(), _k, _v) 

for _k, _v in physical_constants.items() 

if _k not in _obsolete_constants] 

_constant_names = "\n".join(["``%s``%s %s %s" % (_x[1], " "*(66-len(_x[1])), 

_x[2][0], _x[2][1]) 

for _x in sorted(_constant_names)]) 

if __doc__: 

__doc__ = __doc__ % dict(constant_names=_constant_names) 

 

del _constant_names 

 

__all__ = [s for s in dir() if not s.startswith('_')] 

 

from scipy._lib._testutils import PytestTester 

test = PytestTester(__name__) 

del PytestTester