Adding deformation and electric ratio units

[n-tiz]

Pull request for adding 2 (ratio) units:

• Deformation: a dimensionless quantity used to measure deformations in continuum mechanics.
• ElectricRatio: Used to measure an electrical signal which is proportional to the applied excitation voltage (also called ratio-metric system).

[codecov-io]

Codecov Report

Merging #697 into master will decrease coverage by 0.26%.
The diff coverage is 40.65%.

@@            Coverage Diff             @@
##           master     #697      +/-   ##
==========================================
- Coverage   58.34%   58.08%   -0.27%     
==========================================
  Files         165      167       +2     
  Lines       37450    38028     +578     
==========================================
+ Hits        21852    22087     +235     
- Misses      15598    15941     +343

Impacted Files	Coverage Δ
UnitsNet/GeneratedCode/UnitAbbreviationsCache.g.cs	100% <ø> (ø)	⬆️
UnitsNet/GeneratedCode/UnitConverter.g.cs	100% <100%> (ø)	⬆️
UnitsNet/GeneratedCode/Quantities/Deformation.g.cs	36.13% <36.13%> (ø)
...itsNet/GeneratedCode/Quantities/ElectricRatio.g.cs	42.36% <42.36%> (ø)
UnitsNet/GeneratedCode/Quantity.g.cs	81.48% <80%> (-0.03%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1103295...09b93c5. Read the comment docs.

[tmilnthorp]

Does the existing ratio unit not suffice for these? Just curious as it seems to just be a named ratio, but I'm not familiar with these use cases.

[n-tiz]

Does the existing ratio unit not suffice for these? Just curious as it seems to just be a named ratio, but I'm not familiar with these use cases.

In the facts, yes, there are ratio units, but where the current Ratio unit is not linked to physical quantities, theses new units are linked to Length (for Deformation), or ElectricPotential (for ElectricRatio).

The uses cases is to condition a measurement signal from strain gauges.

[angularsen]

@salido-m The only reason we are a bit hesitant to add these quantities is that we are simply trying to avoid the library growing too fat with little-used quantities or if we don't immediately see that it adds enough value, so please bear with us trying to understand the usecase better.

This is not the first time we are debating whether to add quantities and ratio-quantities is a recurring theme since there are so many variations of them. We don't yet have a good guideline for whether a quantity should be added or not, so it's not always easy to decide.

The main reasons I can think of for adding quantities to the library in general are:

• You get Parse() and ToString() out of the box
• Consistent API design and behavior as all the other quantities in Units.NET
• Dynamic conversion and parsing via Quantity and IQuantity
• Arithmetic with the same quantity (add, subtract, multiply and divide)
• Arithmetic with other quantities, f.ex: Torque = Length x Mass
• Convert between units of the same quantitiy
• It is widely used and others will benefit from it or expect it to be in the library

The reasons why custom ratio quantity is useful instead of Ratio:

• You can Parse() and ToString() with the unit abbreviations
• It can be the result of a computation, f.ex: ElectricRatio = ElectricPotential / ElectricPotential
• Strongly typed quantity to pass around in code (although this is easily added per-application)

I've checked the boxes that I think you obtain with ElectricRatio, which does have "meaningful" unit abbreviations as well as multiple units.
Deformation only has one unit and is dimensionless so I feel perhaps it adds less value over simply using Ratio?

Could you perhaps give a short pseudo code example that illustrates why adding these quantities would be useful to you and others, and why using Ratio or providing your own app-specific types would not be as good or not very useful at all? It would help us decide for this and future ratio quantities, thanks!

[angularsen]

Following up on this, do you have any thoughts on my previous comments and questions? It would be helpful to better understand your use cases. Thanks!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.