CONVENTION: ‘$EQ$’, ‘$E$’, ‘eq$’ and ‘sym$’: Examples from the Psy` Psychrometrics package

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Tutorial

[TECHNICAL SLIDE TRAIL] The Webel libraries for Wolfram Mathematica: With SysMLv1 models.

Section

SECTION: CASE STUDY: Applications of the Webel MTools class extensions to Psychrometrics (humid air physics). With SysMLv1 models.

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Mathematica keywords

MTools

Webel Mathematica keywords

Keywords

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For reference, some associated Policy Notes (you don't need to visit these links yet):

Webel: Mathematica: CONVENTION: A '$EQ$' in a function name indicates that it is a symbolic equation (with LHS == RHS). An '$EQ$ function can be used in combination with 'sym$' markup to create human-friendly formatted equations.

Webel: Mathematica: CONVENTION: An '$E$' in a function name indicates that it is symbolic (takes Blank expression arguments). An '$E$' function can also be used with Quantity inputs and can be used to generate '$C$' compiled function variants.

Webel: Mathematica: CONVENTION: A prefix 'sym$' indicates a markup variable "symbol" for a documented variable. It need not be a String, but each referenced part MUST be a String - not a Mathematica Symbol - to avoid namespace clashes!

And a subtle "loophole" policy (to cover some Webel physics library functions that preceded introduction of the '$E$' and '$EQ$' policies):

Webel: Mathematica: CONVENTION: An '$E$' or '$EQ$' in a function name indicates that it is symbolic (takes Blank expression arguments), but the absence of '$E$' or '$EQ$' does not necessarily imply that it does not take Blank arguments.

There is more explanation and demonstration of these conventions in this previous slide from an earlier trail section:

Var` package: ‘sym$’ markup reused in ‘$E$’ functions

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About the Psy` package Psychrometrics exercises slides (in this trail)

Notes

[CAPABILITY, EXPLANATION]{INFORMATIVE} Webel: Psy/MPsy: Psychrometrics for Mathematica: The default MPsy class is a readonly one-shot class that pre-builds many frequently used psychrometric properties (offered as public fields) using CoolProp, and also offers some value-adding methods.

[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Humidity ratio (absolute humidity) is indicated by a lower case 'w' and measured in mass (water) / mass (dry air) units, so the SI and IP representations are equal Real (without an explicit unit system)

[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Relative humidity is indicated by a lower case 'r' and measured as a Real fraction (rather than as a Percentage). [Some tables and plots do SHOW the relative humidity as a Percentage.]

[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Due to Mathematica's units-aware Quantity algebra system it is irrelevant what units are used for the input Quantities for creation of the MPsy objects, as long as they are dimensionally consistent!

[CONVENTION]{INFORMATIVE} Webel: Psy/MPsy: Psychrometrics for Mathematica: Most CoolProp wrappers can be invoked with the dry bulb temperature 'tdb', the pressure 'p', and one (only) of the relative humidity 'r', the humidity ratio 'w', or the wet bulb temperature 'twb'

[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: CONVENTION: 'Q' as a quantity symbol in equations indicates the energy GAINED BY the system as heat energy transfer; 'W' indicates the work DONE BY the system on its external surroundings.

[CONVENTION]{STRICT} Webel: Psy/MPsy: Psychrometrics for Mathematica: Transferred heat (energy "Q") has field names with lower case 'qTot', 'qSen', 'qLat'. Heat rates (energy per time) have field names 'qDotTot', 'qDotSen', 'qDotLat' (to avoid clashes with Mathematica core)

[CONVENTION, NAMING, PATTERN, POLICY]{STRICT} Webel: Mathematica: CONVENTION: A '$EQ$' in a function name indicates that it is a symbolic equation (with LHS == RHS). An '$EQ$ function can be used in combination with 'sym$' markup to create human-friendly formatted equations.

[CONVENTION, NAMING, PATTERN, POLICY]{STRICT} Webel: Mathematica: CONVENTION: An '$E$' in a function name indicates that it is symbolic (takes Blank expression arguments). An '$E$' function can also be used with Quantity inputs and can be used to generate '$C$' compiled function variants.

[CONVENTION, NAMING]{STRICT} Webel: Mathematica: CONVENTION: A prefix 'sym$' indicates a markup variable "symbol" for a documented variable. It need not be a String, but each referenced part MUST be a String - not a Mathematica Symbol - to avoid namespace clashes!

[CONVENTION, NAMING, PATTERN, POLICY]{STRICT} Webel: Mathematica: CONVENTION: An '$E$' or '$EQ$' in a function name indicates that it is symbolic (takes Blank expression arguments), but the absence of '$E$' or '$EQ$' does not necessarily imply that it does not take Blank arguments.

Snippets (quotes/extracts)

Visit also

TRAIL: Air Conditioning Psychrometrics (vs CED Engineering course): Example results (only) in Mathematica and SysML using the Webel Psy package and MPsy class

Visit also (backlinks)

Related slides (includes other tutorials)

Overview of the Psy` package and the "one shot" MPsy humid air state class

The MPsy “one shot” humid air state class

MPsy object creation examples

Psychrometrics exercise references (and about some naming conventions)

Introduction to the Webel All` package and the MAll universal class extending MTools

Psy`Psychrometrics package variables registry

Var` package: ‘sym$’ markup reused in ‘$E$’ functions

Related slides (backlinks, includes other tutorials)

‘$E$’, ‘$Q$’,‘$SI$’ and ‘$C$’ function variants: Simple demo using a trivial Psy` function

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