Scripting

Tengo scripting language

A calculation script makes use of a scripting language, called Tengo.

Tengo is a scripting language written in Go, with a Go-like syntax. Below, you’ll find some resources to help you get started:

Basic syntax overview

Interactive playground

Full documentation

Input data reference(s) via alias

To access the data of an input data reference, one can use the according alias for the input data reference given in the calculation settings. The alias contains the following properties:

Value: the value of the data reference

Timestamp: the timestamp of the data reference

Tags: the tags of the data reference

The properties are case sensitive, so e.g. value will not work.

Example

This example uses the Value property of an alias _A to access the value of an input data reference and multiplies that value by 2.

return _A.Value * 2

Calculation context helper functions

set_tag: set_tag(tag, value) sets a tag in the result

set_status: set_status(status) sets the status of the result

Accessing Metadata

You can access metadata in different contexts, including metadata for the calculation itself or metadata for inputs. These inputs can be either asset properties or measurements. Additionally, if the input is an asset property, you can also access the metadata of the associated asset.

Accessing Metadata of the Calculation Itself

To access the metadata of the calculation itself, use:

factry.get_metadata("<metadata-key>")

Replace <metadata-key> with the key you need.

Accessing Metadata of Inputs

Inputs can be either measurements or asset properties, and the metadata can be accessed as follows:

Accessing Metadata of Measurements or Asset Properties

To access a specific metadata key of an input (either a measurement or asset property):

factry.get_input_metadata("<input-alias>", "<metadata-key>")

Replace <input-alias> with the alias of the input data and <metadata-key> with the key you need. To access all metadata of an input:

metadata := factry.get_input_metadata("<input-alias>")

You can then retrieve specific keys:

metadata["<metadata-key>"]

Accessing Metadata of the Asset (When Input is an Asset Property)

If the input is an asset property, you can also access the metadata of the associated asset:

To access a specific metadata key of the associated asset:

factry.get_input_asset_metadata("<input-alias>", "<metadata-key>")

To access all metadata of the associated asset:

metadata := factry.get_input_asset_metadata("<input-alias>")

Retrieve a specific key as needed:

metadata["<metadata-key>"]

Standard Tengo libraries

The following is a list of standard Tengo libraries that are always available and do not need to be imported in your script. For example, you can use math directly without assigning it using math := import("math").

math

Defines some mathematic constants and functions.

More info

times

Defines some basic time based constants and functions.

More info

time_weekday: times.time_weekday(t time) returns an integer that represents the day of the week of a given timestamp. The numeric representation of weekdays start from 0 with Sunday and end at 6 with Saturday.

Example:

tz := "Europe/Brussels"
ts := times.to_location(_A.Timestamp, tz)
diw := times.time_weekday(ts) // numeric representation of the day of week
hid := times.time_hour(ts) // hour of the day

if diw >= 0.0 && diw <= 5.0 && hid >= 5.0 && hid < 13.0 {
  return 1.0
}

if diw >= 0.0 && diw <= 5.0 && hid >= 13.0 && hid < 21.0 {
  return 2.0
}

if diw >= 0.0 && diw <= 5.0 && hid >= 21.0 && hid < 5.0 {
   return 3.0
}

if diw >= 6.0 && diw <= 7.0 && hid >= 5.0 && hid < 17.0 {
  return 4.0
}

if diw >= 6.0 && diw <= 7.0 && hid >= 17.0 && hid < 5.0 {
  return 4.0
}

rand

Defines functions to generate random values.

More info

text

Defines string manipulation and formatting functions.

More info

enum

Defines some functions to work with enumerables.

More info

Factry Tengo libraries

We’ve added some custom libraries on top of the existing libraries to allow for more versatile scripts.

local

Local allows to save variables in a local context specific to a particular calculation. Only this calculation script can store/retrieve the value across all script executions. The key Context is reserved for the calculation contextcalculation context and can’t be used with these functions.

An overview of the available functions:

get: local.get(key, [defaultValue]) retrieves a value from the local context by its key, with an optional default value to be used when the retrieved value is undefined.

set: local.set(key, value) sets a value in the local context by its key.

Example:

This example retrieves a previously set value from the local context. If the value does not exist, a default value 0.0 is used. After adding 1.0 to the result, the value is set again in the local context and returned as output by the script.

previous := float(local.get("previous"),0.0)
result := previous + 1.0
local.set("previous", result)
return result

global

Global allows to save variables in a global context accessible to all calculation scripts. Any calculation script can store/retrieve the value across all scripts executions. An overview of the available functions:

get: global.get(key, [defaultValue]) retrieves a value from the global context by its key, with an optional default value to be used when the retrieved value is undefined.

set: global.set(key, value) sets a value in the global context by its key.

util

Util provides custom functions for basic operations which are not available or incomplete in the standard Tengo library.

is_equal: checks whether 2 objects are equal, providers better handling of undefined values

Examples

Simple boolean comparison

if is_equal(_A.Value, true) {
  return _B.Value
}

return _C.Value

Comparing numeric types, in this example _A.Value is of type float

return is_equal(_A.Value, 12)

units

Units provides simple unit conversion. Its main datatype is the Value, which represents a number with a given unit. When a Value is returned from a script, it is automatically converted to the bare number. All functions that accept the name of a unit accept the the shorthand of the unit, the singular or plural form of the unit name, and varying spellings of the unit name, eg. m, meter, meters, metre, metres.

convert:

units.convert(input, unit) converts the input into a Value. If input is a number, a new Value is returned with the given unit. If the input is already a Value, the input is converted into the given unit. Conversions can be done between different magnitudes, e.g. meter to kilometer, and between different systems, e.g. Celsius to Fahrenheit, or meters to feet.

units.convert(input, from, to) converts the given number from one unit into another, returning a number.

float: units.float(value) returns the number stored in the Value.

find: units.find(unit) returns the unit object for the given unit. The unit object can be used to add units to numbers, or to convert between units.

Supported units

Pressure

Unit	Names
attopascal	attopascal,aPa,attopascals
femtopascal	femtopascal,fPa,femtopascals
picopascal	picopascal,pPa,picopascals
nanopascal	nanopascal,nPa,nanopascals
micropascal	micropascal,μPa,micropascals
millipascal	millipascal,mPa,millipascals
centipascal	centipascal,cPa,centipascals
decipascal	decipascal,dPa,decipascals
pascal	pascal,Pa,pascals
decapascal	decapascal,daPa,decapascals
hectopascal	hectopascal,hPa,hectopascals
kilopascal	kilopascal,kPa,kilopascals
megapascal	megapascal,MPa,megapascals
gigapascal	gigapascal,GPa,gigapascals
terapascal	terapascal,TPa,terapascals
petapascal	petapascal,PPa,petapascals
exapascal	exapascal,EPa,exapascals
microbar	microbar,μbar,microbars
millibar	millibar,mbar,millibars
centibar	centibar,cbar,centibars
bar	bar,bars
millimeter of Mercury	millimeter of Mercury,mmmHg,millimeter of Mercurys
centimeter of Mercury	centimeter of Mercury,cmmHg,centimeter of Mercurys
meter of Mercury	meter of Mercury,mmHg,meters of Mercury,meters of Mercury
inch of Mercury	inch of Mercury,inHg,inch of Mercurys
millimeter of Water Column	millimeter of Water Column,mmmH2O,millimeter of Water Columns
centimeter of Water Column	centimeter of Water Column,cmmH2O,centimeter of Water Columns
meter of Water Column	meter of Water Column,mmH2O,meters of Water Column,meters of Water Column
inch of Water Column	inch of Water Column,inH2O,inch of Water Columns
newton per square meter	newton per square meter,N/m²,newton per square meters
pound-force per square inch	pound-force per square inch,psi,pound-force per square inchs
standard atmosphere	standard atmosphere,atm,standard atmospheres,standard atmospheres
technical atmosphere	technical atmosphere,at,technical atmospheres,technical atmospheres
torr	torr,Torr,torrs
barye	barye,Ba,baryes,baryes

Time

Unit	Names
attosecond	attosecond,as,attoseconds
femtosecond	femtosecond,fs,femtoseconds
picosecond	picosecond,ps,picoseconds
nanosecond	nanosecond,ns,nanoseconds
microsecond	microsecond,μs,microseconds
millisecond	millisecond,ms,milliseconds
centisecond	centisecond,cs,centiseconds
decisecond	decisecond,ds,deciseconds
second	second,s,seconds
decasecond	decasecond,das,decaseconds
hectosecond	hectosecond,hs,hectoseconds
kilosecond	kilosecond,ks,kiloseconds
megasecond	megasecond,Ms,megaseconds
gigasecond	gigasecond,Gs,gigaseconds
terasecond	terasecond,Ts,teraseconds
petasecond	petasecond,Ps,petaseconds
exasecond	exasecond,Es,exaseconds
minute	minute,min,minutes
hour	hour,hr,hours
day	day,d,days
fortnight	fortnight,fortnights
month	month,months
year	year,yr,years
decade	decade,decades
score	score,scores
century	century,centurys
millennium	millennium,millenniums
planck time	planck time,𝑡ₚ,planck times

Bits/Bytes

Unit	Names
bit	bit,b,bits
kilobit	kilobit,kb,kilobits
megabit	megabit,Mb,megabits
gigabit	gigabit,Gb,gigabits
terabit	terabit,Tb,terabits
petabit	petabit,Pb,petabits
exabit	exabit,Eb,exabit

Unit	Names
nibble	nibble,nibbles
byte	byte,B,bytes
kilobyte	kilobyte,KB,kilobytes
kibibyte	kibibyte,KiB,kibibytes
megabyte	megabyte,MB,megabytes
mebibyte	mebibyte,MiB,mebibytes
gigabyte	gigabyte,GB,gigabytes
gibibyte	gibibyte,GiB,gibibytes
terabyte	terabyte,TB,terabytes
tebibyte	tebibyte,TiB,tebibytes
petabyte	petabyte,PB,petabytes
pebibyte	pebibyte,PiB,pebibytes
exabyte	exabyte,exabytes
exbibyte	exbibyte,EiB,exbibytes
zettabyte	zettabyte,zettabytes
zebibyte	zebibyte,ZiB,zebibytes
yottabyte	yottabyte,yottabytes
yobibyte	yobibyte,YiB,yobibytes

Energy

Unit	Names
attojoule	attojoule,aJ,attojoules
femtojoule	femtojoule,fJ,femtojoules
picojoule	picojoule,pJ,picojoules
nanojoule	nanojoule,nJ,nanojoules
microjoule	microjoule,μJ,microjoules
millijoule	millijoule,mJ,millijoules
joule	joule,J,joules
kilojoule	kilojoule,kJ,kilojoules
megajoule	megajoule,MJ,megajoules
gigajoule	gigajoule,GJ,gigajoules
terajoule	terajoule,TJ,terajoules
petajoule	petajoule,PJ,petajoules
exajoule	exajoule,EJ,exajoules
zettajoule	zettajoule,ZJ,zettajoules
yottajoule	yottajoule,YJ,yottajoules
calorie	calorie,cal,calories
electronvolt	electronvolt,eV,electronvolts
watt-hour	watt-hour,Wh,watt-hours
kilowatt-hour	kilowatt-hour,kWh,kilowatt-hours
megawatt-hour	megawatt-hour,MWh,megawatt-hours
gigawatt-hour	gigawatt-hour,GWh,gigawatt-hours
terawatt-hour	terawatt-hour,TWh,terawatt-hours
petawatt-hour	petawatt-hour,PWh,petawatt-hours

Power

Unit	Names
watt	watt,W,watts
kilowatt	kilowatt,kW,kilowatts
megawatt	megawatt,MW,megawatts
gigawatt	gigawatt,GW,gigawatts
terawatt	terawatt,TW,terawatts
petawatt	petawatt,PW,petawatts
exawatt	exawatt,EW,exawatts
zettawatt	zettawatt,ZW,zettawatts
yottawatt	yottawatt,YW,yottawatts

Temperature

Unit	Names
celsius	celsius,C
fahrenheit	fahrenheit,F
kelvin	kelvin,K

Volume

Unit	Names
attoliter	attoliter,al,attolitre,attoliters
femtoliter	femtoliter,fl,femtolitre,femtoliters
picoliter	picoliter,pl,picolitre,picoliters
nanoliter	nanoliter,nl,nanolitre,nanoliters
microliter	microliter,μl,microlitre,microliters
milliliter	milliliter,ml,millilitre,milliliters
centiliter	centiliter,cl,centilitre,centiliters
deciliter	deciliter,dl,decilitre,deciliters
liter	liter,l,litre,liters
decaliter	decaliter,dal,decalitre,decaliters
hectoliter	hectoliter,hl,hectolitre,hectoliters
kiloliter	kiloliter,kl,kilolitre,kiloliters
megaliter	megaliter,Ml,megalitre,megaliters
gigaliter	gigaliter,Gl,gigalitre,gigaliters
teraliter	teraliter,Tl,teralitre,teraliters
petaliter	petaliter,Pl,petalitre,petaliters
exaliter	exaliter,El,exalitre,exaliters
customary fluid ounce	customary fluid ounce,customary fluid ounces
fluid ounce	fluid ounce,fl oz,floz,fluid ounces
fluid pint	fluid pint,fl pt,fluid pints
fluid quart	fluid quart,fl qt,fluid quarts
fluid gallon	fluid gallon,fluid gallons
pint	pint,pt,pints
quart	quart,qt,quarts
gallon	gallon,gal,gallons

Length

Unit	Names
attometer	attometer,am,attometre,attometers
femtometer	femtometer,fm,femtometre,femtometers
picometer	picometer,pm,picometre,picometers
nanometer	nanometer,nm,nanometre,nanometers
micrometer	micrometer,μm,micrometre,micrometers
millimeter	millimeter,mm,millimetre,millimeters
centimeter	centimeter,cm,centimetre,centimeters
decimeter	decimeter,dm,decimetre,decimeters
meter	meter,m,metre,meters
decameter	decameter,dam,decametre,decameters
hectometer	hectometer,hm,hectometre,hectometers
kilometer	kilometer,km,kilometre,kilometers
megameter	megameter,Mm,megametre,megameters
gigameter	gigameter,Gm,gigametre,gigameters
terameter	terameter,Tm,terametre,terameters
petameter	petameter,Pm,petametre,petameters
exameter	exameter,Em,exametre,exameters
angstrom	angstrom,Å,angstroms,angstroms
inch	inch,in,inches,inches
foot	foot,ft,feet,feet
yard	yard,yd,yards
mile	mile,mi,miles
furlong	furlong,fur,furlongs
league	league,lea,leagues

Mass

Unit	Names
attogram	attogram,ag,attograms
femtogram	femtogram,fg,femtograms
picogram	picogram,pg,picograms
nanogram	nanogram,ng,nanograms
microgram	microgram,μg,micrograms
milligram	milligram,mg,milligrams
centigram	centigram,cg,centigrams
decigram	decigram,dg,decigrams
gram	gram,g,grams
decagram	decagram,dag,decagrams
hectogram	hectogram,hg,hectograms
kilogram	kilogram,kg,kilograms
megagram	megagram,Mg,megagrams
gigagram	gigagram,Gg,gigagrams
teragram	teragram,Tg,teragrams
petagram	petagram,Pg,petagrams
exagram	exagram,Eg,exagrams
drachm	drachm,dr,drachms
grain	grain,gr,grains
ounce	ounce,oz,ounces
pound	pound,lb,pounds
slug	slug,slugs
stone	stone,st,stones
ton	ton,t,tons

Examples

Unit conversion

// Convert 1000 meters to kilometers
// 1. convert the number 1000 to a Value with unit "m"
meters := units.convert(1000, "m")
// 2. convert the Value to kilometers
kilometers := units.convert(meters, "km")
// 3. return the number stored in the Value
// note that this conversion is not necessary, as the result is automatically converted to a number
kilometersFloat := units.float(kilometers)
return kilometersFloat

Unit conversion with find

// Convert 20 degrees Celsius to Kelvin, and convert 30 degrees Celsius to Fahrenheit
celsius := units.find("C")
kelvin := units.find("K")
fahrenheit := units.find("F")
twentyC := celsius(20)
thirtyC := celsius(30)

twentyK := units.convert(twentyC, kelvin)
thirtyF := units.convert(thirtyC, fahrenheit)
return [units.float(twentyK), units.float(thirtyF)]

Unit conversion with from and to

// Convert 1000 meters to kilometers
// 1. convert the number 1000 from "m" to "km"
kilometers := units.convert(1000, "metre", "kilometer")
// 2. return the number
return kilometers

if97

IF97 provides functions for calculating thermodynamic properties of steam and water according to the IAPWS IF97 specification. This module uses names for thermodynamic quantities as defined on page 3 of the specification PDF.

All IF97 functions take either a regular number or a units.Value unit-aware value as input. Units will be converted where needed. Return values are also unit.Value objects.

if97 functions

massDensity: if97.massDensity(temp, pressure) returns the mass density (kg/m^3) as a function of temperature (K) and pressure (Pa) specificEnthalpy: if97.specificEnthalpy(temp, pressure) returns the specific enthalpy (J/kg) as a function of temperature (K) and pressure (Pa) specificEntropy: if97.specificEntropy(temp, pressure) returns the specific entropy (J/kg/K) as a function of temperature (K) and pressure (Pa) specificInternalEnergy: if97.specificInternalEnergy(temp, pressure) returns the specific internal energy (J/kg) as a function of temperature (K) and pressure (Pa) isobaricHeatCap: if97.isobaricHeatCap(temp, pressure) returns the mass constant-pressure heat capacity (J/kg/K) as a function of temperature (K) and pressure (Pa) isochoricHeatCap: if97.isochoricHeatCap(temp, pressure) returns the mass constant-volume heat capacity (J/kg/K) as a function of temperature (K) and pressure (Pa) speedSound: if97.speedSound(temp, pressure) returns the speed of sound (m/s) as a function of temperature (K) and pressure (Pa) derivMassDensityPressure: if97.derivMassDensityPressure(temp, pressure) returns (d(rho)/d(p))T (kg/m³/Pa) as a function of temperature (K) and pressure (Pa) viscosity: if97.viscosity(temp, pressure) returns the viscosity (Pa-s) as a function of temperature (K) and pressure (Pa) thermalConductivity: if97.thermalConductivity(temp, pressure) returns the thermal conductivity (W/m-K) as a function of temperature (K) and pressure (Pa) prandtl: if97.prandtl(temp, pressure) returns the Prandtl number (dimensionless) as a function of temperature (K) and pressure (Pa) satLiquidMassDensity: if97.satLiquidMassDensity(pressure) returns the saturated liquid mass density (kg/m^3) as a function of pressure (Pa) satVaporMassDensity: if97.satVaporMassDensity(pressure) returns the saturated vapor mass density (kg/m^3) as a function of pressure (Pa) satLiquidSpecificEnthalpy: if97.satLiquidSpecificEnthalpy(pressure) returns the saturated liquid specific enthalpy (J/kg) as a function of pressure (Pa) satVaporSpecificEnthalpy: if97.satVaporSpecificEnthalpy(pressure) returns the saturated vapor specific enthalpy (J/kg) as a function of pressure (Pa) satLiquidSpecificEntropy: if97.satLiquidSpecificEntropy(pressure) returns the saturated liquid specific entropy (J/kg/K) as a function of pressure (Pa) satVaporSpecificEntropy: if97.satVaporSpecificEntropy(pressure) returns the saturated vapor specific entropy (J/kg/K) as a function of pressure (Pa) satLiquidMassInternalEnergy: if97.satLiquidMassInternalEnergy(pressure) returns the saturated liquid mass internal energy (J/kg) as a function of pressure (Pa) satVaporMassInternalEnergy: if97.satVaporMassInternalEnergy(pressure) returns the saturated vapor mass internal energy (J/kg) as a function of pressure (Pa) satLiquidIsobaricHeatCap: if97.satLiquidIsobaricHeatCap(pressure) returns the saturated liquid isobaric heat capacity (J/kg/K) as a function of pressure (Pa) satVaporIsobaricHeatCap: if97.satVaporIsobaricHeatCap(pressure) returns the saturated vapor isobaric heat capacity (J/kg/K) as a function of pressure (Pa) satLiquidIsochoricHeatCap: if97.satLiquidIsochoricHeatCap(pressure) returns the saturated liquid isochoric heat capacity (J/kg/K) as a function of pressure (Pa) satVaporIsochoricHeatCap: if97.satVaporIsochoricHeatCap(pressure) returns the saturated vapor isochoric heat capacity (J/kg/K) as a function of pressure (Pa) satLiquidSpeedSound: if97.satLiquidSpeedSound(pressure) returns the saturated liquid speed of sound (m/s) as a function of pressure (Pa) satVaporSpeedSound: if97.satVaporSpeedSound(pressure) returns the saturated vapor speed of sound (m/s) as a function of pressure (Pa) satLiquidViscosity: if97.satLiquidViscosity(pressure) returns the saturated liquid viscosity (Pa-s) as a function of pressure (Pa) satVaporViscosity: if97.satVaporViscosity(pressure) returns the saturated vapor viscosity (Pa-s) as a function of pressure (Pa) satLiquidThermalCond: if97.satLiquidThermalCond(pressure) returns the saturated liquid thermal conductivity (W/m-K) as a function of pressure (Pa) satVaporThermalCond: if97.satVaporThermalCond(pressure) returns the saturated vapor thermal conductivity (W/m-K) as a function of pressure (Pa) satLiqPrandtl: if97.satLiqPrandtl(pressure) returns the saturated liquid Prandtl number (dimensionless) as a function of pressure (Pa) satVaporPrandtl: if97.satVaporPrandtl(pressure) returns the saturated vapor Prandtl number (dimensionless) as a function of pressure (Pa) satTemp: if97.satTemp(pressure) returns the saturation temperature (K) as a function of pressure (Pa) satPressure: if97.satPressure(temp) returns the saturation pressure (Pa) as a function of temperature (K) surfaceTension: if97.surfaceTension(temp) returns the surface tension (N/m) as a function of temperature (K) backwardEnthalpyTemp: if97.backwardEnthalpyTemp(pressure, specific_enthalpy) returns the temperature (K) as a function of pressure (Pa) and specific enthalpy (J/kg) backwardEnthalpyMassDensity: if97.backwardEnthalpyMassDensity(pressure, specific_enthalpy) returns the mass density (kg/m^3) as a function of pressure (Pa) and specific enthalpy (J/kg) backwardEntropyTemp: if97.backwardEntropyTemp(pressure, specific_entropy) returns the temperature (K) as a function of pressure (Pa) and specific entropy (J/kg/K) backwardEntropyMassDensity: if97.backwardEntropyMassDensity(pressure, specific_entropy) returns the mass density (kg/m^3) as a function of pressure (Pa) and specific entropy (J/kg/K) backwardPressure: if97.backwardPressure(specific_enthalpy, specific_entropy) returns the pressure (Pa) as a function of specific enthalpy (J/kg) and specific entropy (J/kg/K) backwardTemp: if97.backwardTemp(specific_enthalpy, specific_entropy) returns the temperature (K) as a function of specific enthalpy (J/kg) and specific entropy (J/kg/K) backwardEntropyEnthalpy: if97.backwardEntropyEnthalpy(pressure, specific_entropy) returns the specific enthalpy (J/kg) as a function of pressure (Pa) and specific entropy (J/kg/K) backwardEnthalpyEntropy: if97.backwardEnthalpyEntropy(pressure, specific_enthalpy) returns the specific entropy (J/kg/K) as a function of pressure (Pa) and specific enthalpy (J/kg) qualitySpecificEnthalpy: if97.qualitySpecificEnthalpy(pressure, vapor_quality) returns the specific enthalpy (J/kg) as a function of pressure (Pa) and vapor quality (%) qualitySpecificInternalEnergy: if97.qualitySpecificInternalEnergy(pressure, vapor_quality) returns the specific internal energy (J/kg) as a function of pressure (Pa) and vapor quality (%) qualitySpecificEntropy: if97.qualitySpecificEntropy(pressure, vapor_quality) returns the specific entropy (J/kg/K) as a function of pressure (Pa) and vapor quality (%) qualitySpecificVolume: if97.qualitySpecificVolume(pressure, vapor_quality) returns the specific volume (m^3) as a function of pressure (Pa) and vapor quality (%) qualityMassDensity: if97.qualityMassDensity(pressure, specific_enthalpy) returns the mass density (kg/m^3) as a function of pressure (Pa) and vapor quality (%) specificEnthalpyQuality: if97.specificEnthalpyQuality(pressure, specific_enthalpy) returns the vapor quality (%) as a function of pressure (Pa) and specific enthalpy (J/kg) specificInternalEnergyQuality: if97.specificInternalEnergyQuality(pressure, specific_internal_energy) returns the vapor quality (%) as a function of pressure (Pa) and specific internal energy (J/kg) specificEntropyQuality: if97.specificEntropyQuality(pressure, specific_entropy) returns the vapor quality (%) as a function of pressure (Pa) and specific entropy (J/kg/K) massDensityQuality: if97.massDensityQuality(pressure, mass_density) returns the vapor quality (%) as a function of pressure (Pa) and mass density (kg/m^3) specificVolumeQuality: if97.specificVolumeQuality(pressure, specific_volume) returns the vapor quality (%) as a function of pressure (Pa) and specific volume (m^3)