SYSML17 — Suggest introduce an operation to obtain the magnitude of a value property in a given compatible Unit (to afford equality comparison)

Spawned from SYSML17-31 to help support comparisons for BindingConnector.

Suggest introduce an operation to obtain the magnitude of a value property in a given compatible Unit (to afford equality comparison)

A compatible Unit is any Unit that has the same fundamental Dimensions as the Unit of the value property for which the magnitude is to be obtained. It need not be (but typically would be) from the same Unit system.

[EDIT: See attached Wolfram Mathematica example with CompatibleUnitQ example]

Equality of values of value properties at the ends of a BindingConnector can be compared via the proposed operation:

• The case where the two value properties have the same Unit from the same system is trivial.

• In the case where the two value properties have compatible Units (same fundamental Dimensions) from the same system but different scaling factors (say g vs kg), a simple scaling must be performed.

• In the case where the two value properties have compatible Units (same fundamental Dimensions) from different systems (say ft vs km), a conversion and possibly also a scaling must be performed.

This proposal does not restrict tools to use any particular choice of Unit when performing equality comparisons.

This proposal specifically only supports comparison of values of value properties with compatible fundamental Dimensions, but does not involve quantity kind.