Constants - scalanlp/breeze GitHub Wiki

Scala breeze constant values are taken from The NIST Reference on Constants, Units and Uncertainty (2010), and are in SI units. Selected constants are available directly, the other NIST constants are available via database search.

##Accessing CODATA2010 constants

import breeze.numerics.constants._

Regex versions of the function will return a Vector of a Tuple2 of the matched value names and value. (i.e. val values: Vector[(String, Double)] = Database.value(regex))

	Breeze	Scipy
a list of values	`Database.list()`	``
specific value	`Database.value(string: String)`	`value(key)`
(value by regex)	`Database.value(regex: Regex)` i.e. `Database.value("""regex string""".r)`
uncertainty	`Database.uncertainty(string: String)`	`precision(key)`
(uncertainty by regex)	`Database.uncertainty (regex: Regex)`
unit	`Database.unit (string: String)`	`unit (key)`
(unit by regex)	`Database.unit (regex: Regex)`

##Accessing selected constants directly import breeze.numerics.constants._

Mathematical

Constant	Breeze	Scipy
	`breeze.numerics.constants._`	`scipy.constants._`
Pi	`Pi`	`pi`
golden ratio	`GoldenRatio`	`golden`

Electromagnetic

Constant	Breeze	Scipy
	`breeze.numerics.constants._`	`scipy.constants._`
magnetic constant	`MagneticConstant` or `Mu0`	`mu_0`
electric constant (vacuum permittivity)	`ElectricConstant` or `Epsilon0`	`epsilon_0`
fine structure constant	`FineStructureConstant` or `Alpha`	`alpha`

Mechanics

Constant	Breeze	Scipy
	`breeze.numerics.constants._`	`scipy.constants._`
gravitation constant	`GravitationConstant`	`G`
standard acceleration of gravity	`StandardAccelerationOfGravity` or `g`	`g`

Thermodynamics

Constant	Breeze	Scipy
	`breeze.numerics.constants._`	`scipy.constants._`
Avogadro number	`AvogadroNumber` or `NA`	`N_A`
molar gas constant	`MolarGasConstant` or `R`	`R`
Boltzmann constant	`BoltzmannConstant` or `k`	`k`

Particle

Constant	Breeze	Scipy
	`breeze.numerics.constants._`	`scipy.constants._`
light speed	`LightSpeed` or `c`	`c`
Planck constant	`PlanckConstant` or `h`	`h`
h bar === h/(2 Pi)	`hBar`	`hbar`
elementary charge	`ElementaryCharge` or `e`	`e`
electron mass	`ElectronMass`	`m_e`
proton mass	`ProtonMass`	`m_p`
neutron mass	`NeutronMass`	`m_n`
Rydberg constant	`RydbergConstant`	`Rydberg`
Wien displacement law constant	`WienDisplacementLawConstant` or `Wien`	`Wien`
Stefan-Boltzmann constant	`StefanBoltzmannConstant` or `sigma`	`sigma`

SI Prefixes

Constant (Breeze/Scipy)	value
`yotta`	1E24
`zetta`	1E21
`exa`	1E18
`peta`	1E15
`tera`	1E12
`giga`	1E9
`mega`	1E6
`kilo`	1E3
`hecto`	1E2
`deca` (`deka` in Scipy)	1E1
`deci`	1E-1
`centi`	1E-2
`milli`	1E-3
`micro`	1E-6
`nano`	1E-9
`pico`	1E-12
`femto`	1E-15
`atto`	1E-18
`zepto`	1E-21
`yocto` (not present in Scipy)	1E-24

ICE Binary Prefixes

Constant (Breeze/Scipy)	value
`kibi`	2^10
`mebi`	2^20
`gibi`	2^30
`tebi`	2^40
`pebi`	2^50
`exbi`	2^60
`zebi`	2^70
`yobi`	2^80