Unit conversion utility. More...

#include <Units.h>

Public Member Functions
	UnitSystem (std::initializer_list< std::string > units)
	Create a unit system with the specified default units. More...

	UnitSystem ()
	Default constructor for unit system (needed as VS2019 does not recognize an optional argument with a default value) More...

void	setDefaults (std::initializer_list< std::string > units)
	Set the default units to convert from when explicit units are not provided. More...

void	setDefaults (const std::map< std::string, std::string > &units)
	Set the default units using a map of dimension to unit pairs. More...

void	setDefaultActivationEnergy (const std::string &e_units)
	Set the default units to convert from when using the `convertActivationEnergy` function. More...

double	convert (double value, const std::string &src, const std::string &dest) const
	Convert `value` from the units of `src` to the units of `dest`. More...

double	convert (double value, const Units &src, const Units &dest) const

double	convert (double value, const std::string &dest) const
	Convert `value` from this unit system (defined by `setDefaults`) to the specified units. More...

double	convert (double value, const Units &dest) const

double	convert (const AnyValue &val, const std::string &dest) const
	Convert a generic AnyValue node to the units specified in `dest`. More...

double	convert (const AnyValue &val, const Units &dest) const

vector_fp	convert (const std::vector< AnyValue > &vals, const std::string &dest) const
	Convert an array of AnyValue nodes to the units specified in `dest`. More...

vector_fp	convert (const std::vector< AnyValue > &vals, const Units &dest) const

double	convertActivationEnergy (double value, const std::string &src, const std::string &dest) const
	Convert `value` from the units of `src` to the units of `dest`, allowing for the different dimensions that can be used for activation energies. More...

double	convertActivationEnergy (double value, const std::string &dest) const
	Convert `value` from the default activation energy units to the specified units. More...

double	convertActivationEnergy (const AnyValue &val, const std::string &dest) const
	Convert a generic AnyValue node to the units specified in `dest`. More...

Private Attributes
double	m_mass_factor
	Factor to convert mass from this unit system to kg. More...

double	m_length_factor
	Factor to convert length from this unit system to meters. More...

double	m_time_factor
	Factor to convert time from this unit system to seconds. More...

double	m_pressure_factor
	Factor to convert pressure from this unit system to Pa. More...

double	m_energy_factor
	Factor to convert energy from this unit system to J. More...

double	m_activation_energy_factor
	Factor to convert activation energy from this unit system to J/kmol. More...

double	m_quantity_factor
	Factor to convert quantity from this unit system to kmol. More...

bool	m_explicit_activation_energy
	True if activation energy units are set explicitly, rather than as a combination of energy and quantity units. More...

Detailed Description

Unit conversion utility.

Provides functions for converting dimensional values from a given unit system. The main use is for converting values specified in input files to Cantera's native unit system, which is SI units except for the use of kmol as the base unit of quantity, i.e. kilogram, meter, second, kelvin, ampere, and kmol.

String representations of units can be written using multiplication, division, and exponentiation. Spaces are ignored. Positive, negative, and decimal exponents are permitted. Examples:

kg*m/s^2
J/kmol
m*s^-2
J/kg/K

Metric prefixes are recognized for all units, e.g. nm, hPa, mg, EJ, mL, kcal.

Special functions for converting activation energies allow these values to be expressed as either energy per quantity, energy (e.g. eV), or temperature by applying a factor of the Avogadro number or the gas constant where needed.

Definition at line 100 of file Units.h.

Constructor & Destructor Documentation

◆ UnitSystem() [1/2]

UnitSystem ( std::initializer_list< std::string > units )

Create a unit system with the specified default units.

Definition at line 228 of file Units.cpp.

References UnitSystem::setDefaults().

◆ UnitSystem() [2/2]

UnitSystem ( )

inline

Default constructor for unit system (needed as VS2019 does not recognize an optional argument with a default value)

Definition at line 108 of file Units.h.

Member Function Documentation

◆ setDefaults() [1/2]

void setDefaults ( std::initializer_list< std::string > units )

Set the default units to convert from when explicit units are not provided.

Defaults can be set for mass, length, time, quantity, energy, and pressure. Conversion using the pressure or energy units is done only when the target units explicitly contain pressure or energy units.

To use SI+kmol: setDefaults({"kg", "m", "s", "Pa", "J", "kmol"});
To use CGS+mol: setDefaults({"cm", "g", "dyn/cm^2", "erg", "mol"});

Definition at line 241 of file Units.cpp.

References UnitSystem::m_activation_energy_factor, UnitSystem::m_energy_factor, UnitSystem::m_explicit_activation_energy, UnitSystem::m_length_factor, UnitSystem::m_mass_factor, UnitSystem::m_pressure_factor, UnitSystem::m_quantity_factor, and UnitSystem::m_time_factor.

Referenced by AnyValue::applyUnits(), AnyMap::applyUnits(), and UnitSystem::UnitSystem().

◆ setDefaults() [2/2]

void setDefaults ( const std::map< std::string, std::string > & units )

Set the default units using a map of dimension to unit pairs.

Defaults for dimensions not specified will be left unchanged. To use Cantera's default units:

UnitSystem system;
std::map<string, string> defaults{
    {"length", "m"}, {"mass", "kg"}, {"time", "s"},
    {"quantity", "kmol"}, {"pressure", "Pa"}, {"energy", "J"},
    {"activation-energy", "J/kmol"}
};
setDefaults(defaults);

Definition at line 270 of file Units.cpp.

References Units::convertible(), Units::factor(), UnitSystem::m_activation_energy_factor, UnitSystem::m_energy_factor, UnitSystem::m_explicit_activation_energy, UnitSystem::m_length_factor, UnitSystem::m_mass_factor, UnitSystem::m_pressure_factor, UnitSystem::m_quantity_factor, UnitSystem::m_time_factor, UnitSystem::setDefaultActivationEnergy(), and Units::str().

◆ setDefaultActivationEnergy()

void setDefaultActivationEnergy ( const std::string & e_units )

Set the default units to convert from when using the convertActivationEnergy function.

Definition at line 306 of file Units.cpp.

References Cantera::Avogadro, Units::convertible(), Units::factor(), Cantera::GasConstant, UnitSystem::m_activation_energy_factor, and UnitSystem::m_explicit_activation_energy.

Referenced by UnitSystem::setDefaults().

◆ convert() [1/4]

double convert	(	double	value,
		const std::string &	src,
		const std::string &	dest
	)		const

Convert value from the units of src to the units of dest.

Definition at line 322 of file Units.cpp.

Referenced by AnyMap::convert(), UnitSystem::convert(), AnyMap::convertVector(), PDSS_SSVol::initThermo(), and RedlichKwongMFTP::initThermo().

◆ convert() [2/4]

double convert	(	double	value,
		const std::string &	dest
	)		const

Convert value from this unit system (defined by setDefaults) to the specified units.

Warning: This function is an experimental part of the Cantera API and may be changed or removed without notice.

Definition at line 338 of file Units.cpp.

References UnitSystem::convert().

◆ convert() [3/4]

double convert	(	const AnyValue &	val,
		const std::string &	dest
	)		const

Convert a generic AnyValue node to the units specified in dest.

If the input is a double, convert it using the default units. If the input is a string, treat this as a dimensioned value, e.g. '988 kg/m^3' and convert from the specified units.

Definition at line 372 of file Units.cpp.

References UnitSystem::convert().

◆ convert() [4/4]

vector_fp convert	(	const std::vector< AnyValue > &	vals,
		const std::string &	dest
	)		const

Convert an array of AnyValue nodes to the units specified in dest.

For each node, if the value is a double, convert it using the default units, and if it is a string, treat it as a value with the given dimensions.

Definition at line 389 of file Units.cpp.

References UnitSystem::convert().

◆ convertActivationEnergy() [1/3]

double convertActivationEnergy	(	double	value,
		const std::string &	src,
		const std::string &	dest
	)		const

Convert value from the units of src to the units of dest, allowing for the different dimensions that can be used for activation energies.

Definition at line 405 of file Units.cpp.

References Cantera::Avogadro, Units::convertible(), Units::factor(), and Cantera::GasConstant.

Referenced by UnitSystem::convertActivationEnergy().

◆ convertActivationEnergy() [2/3]

double convertActivationEnergy	(	double	value,
		const std::string &	dest
	)		const

Convert value from the default activation energy units to the specified units.

Warning: This function is an experimental part of the Cantera API and may be changed or removed without notice.

Definition at line 437 of file Units.cpp.

References Cantera::Avogadro, Units::convertible(), Units::factor(), Cantera::GasConstant, and UnitSystem::m_activation_energy_factor.

◆ convertActivationEnergy() [3/3]

double convertActivationEnergy	(	const AnyValue &	val,
		const std::string &	dest
	)		const

Convert a generic AnyValue node to the units specified in dest.

If the input is a double, convert it using the default units. If the input is a string, treat this as a dimensioned value, e.g. '2.7e4 J/kmol' and convert from the specified units.

Definition at line 453 of file Units.cpp.

References UnitSystem::convertActivationEnergy().

Member Data Documentation

◆ m_mass_factor

double m_mass_factor

private

Factor to convert mass from this unit system to kg.

Definition at line 187 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_length_factor

double m_length_factor

private

Factor to convert length from this unit system to meters.

Definition at line 190 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_time_factor

double m_time_factor

private

Factor to convert time from this unit system to seconds.

Definition at line 193 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_pressure_factor

double m_pressure_factor

private

Factor to convert pressure from this unit system to Pa.

Definition at line 196 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_energy_factor

double m_energy_factor

private

Factor to convert energy from this unit system to J.

Definition at line 199 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_activation_energy_factor

double m_activation_energy_factor

private

Factor to convert activation energy from this unit system to J/kmol.

Definition at line 202 of file Units.h.

Referenced by UnitSystem::convertActivationEnergy(), UnitSystem::setDefaultActivationEnergy(), and UnitSystem::setDefaults().

◆ m_quantity_factor

double m_quantity_factor

private

Factor to convert quantity from this unit system to kmol.

Definition at line 205 of file Units.h.

Referenced by UnitSystem::setDefaults().

◆ m_explicit_activation_energy

bool m_explicit_activation_energy

private

True if activation energy units are set explicitly, rather than as a combination of energy and quantity units.

Definition at line 209 of file Units.h.

Referenced by UnitSystem::setDefaultActivationEnergy(), and UnitSystem::setDefaults().

The documentation for this class was generated from the following files:

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ UnitSystem() [1/2]

◆ UnitSystem() [2/2]

Member Function Documentation

◆ setDefaults() [1/2]

◆ setDefaults() [2/2]

◆ setDefaultActivationEnergy()

◆ convert() [1/4]

◆ convert() [2/4]

◆ convert() [3/4]

◆ convert() [4/4]

◆ convertActivationEnergy() [1/3]

◆ convertActivationEnergy() [2/3]

◆ convertActivationEnergy() [3/3]

Member Data Documentation

◆ m_mass_factor

◆ m_length_factor

◆ m_time_factor

◆ m_pressure_factor

◆ m_energy_factor

◆ m_activation_energy_factor

◆ m_quantity_factor

◆ m_explicit_activation_energy