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Inferred division from defined multiplication relations#1354

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angularsen merged 5 commits intoangularsen:release/v6from
Muximize:inferred-division
Mar 1, 2024
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Inferred division from defined multiplication relations#1354
angularsen merged 5 commits intoangularsen:release/v6from
Muximize:inferred-division

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@Muximize Muximize commented Jan 7, 2024 •
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In #1329 this proposal came up:

Another idea: generate division operators based on multiplication. Right now we define:

ElectricPotential.Volt = ElectricCurrent.Ampere * ElectricResistance.Ohm (and generate the reverse)
ElectricCurrent.Ampere = ElectricPotential.Volt / ElectricResistance.Ohm
ElectricResistance.Ohm = ElectricPotential.Volt / ElectricCurrent.Ampere

But those last two could also be generated based on the first.

This PR is an experiment implementing this.

Breaking changes:

  • TimeSpan = Volume / VolumeFlow => Duration = Volume / VolumeFlow

@Muximize Muximize mentioned this pull request Jan 7, 2024
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Muximize commented Jan 25, 2024 •
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I rebased this on the latest changes in #1329 which makes it much cleaner.

Example of an interesting situation that occurs here, we previously defined:

MassFlow.GramPerSecond = Area.SquareMeter * MassFlux.GramPerSecondPerSquareMeter
MassFlux.KilogramPerSecondPerSquareMeter = MassFlow.KilogramPerSecond / Area.SquareMeter

If we infer division from multiplication, one of those has to add or lose a kilo 😅

@Muximize Muximize changed the base branch from master to release/v6 February 4, 2024 19:54
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angularsen commented Feb 5, 2024

Will review this next, hopefully in the next few days.

If we infer division from multiplication, one of those has to add or lose a kilo 😅

Haha 😆 But it will still work, right?
The inferred division will just use grams instead?

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Muximize commented Feb 5, 2024

Yes, it will work, except we're not sure why the original contributor chose a particular unit for an operator and if it matters, with precision for example.

Also, this PR is more of an experiment than a serious proposal. There's some questions about the "magic" of it, and I took some liberties with implicit/explicit conversion between Density and MassConcentration that I'm not quite sure about. Maybe @lipchev can chime in on this?

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lipchev commented Feb 5, 2024

Yes, it will work, except we're not sure why the original contributor chose a particular unit for an operator and if it matters, with precision for example.

Also, this PR is more of an experiment than a serious proposal. There's some questions about the "magic" of it, and I took some liberties with implicit/explicit conversion between Density and MassConcentration that I'm not quite sure about. Maybe @lipchev can chime in on this?

Although the Density and Mass Concentration share the same units, they are not interchangeable- they describe different types of ratios. Casting between them (either implicitly or explicitly) makes no sense..

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Muximize commented Feb 6, 2024

Thanks for the explanation! That makes the concept of inferred division a bit harder, given that we currently have:

Mass.Kilogram = Density.KilogramPerCubicMeter * Volume.CubicMeter
Mass.Kilogram = MassConcentration.KilogramPerCubicMeter * Volume.CubicMeter

which leads to these inferred ambiguous operators, which is what I tried to solve with my casting shenanigans:

Density.KilogramPerCubicMeter           = Mass.Kilogram / Volume.CubicMeter
MassConcentration.KilogramPerCubicMeter = Mass.Kilogram / Volume.CubicMeter

The latter is currently not defined, so skipping it would not be a breaking change. I've reworked this PR to do that and removed the casting stuff.

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I like where this is going and would like to get it merged.
Some comments so far.

@Muximize Muximize mentioned this pull request Feb 19, 2024
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@Muximize Muximize marked this pull request as ready for review February 24, 2024 12:56
@Muximize Muximize force-pushed the inferred-division branch 2 times, most recently from 44bd139 to 1950b51 Compare February 24, 2024 13:08
angularsen added a commit that referenced this pull request Feb 26, 2024
@Muximize @angularsen
Implicit cast between Duration and TimeSpan (#1365)
240b19d 
### Changes
- Change `Duration` from explicit to implicit cast to/from `TimeSpan`
- Remove operator overloads for `TimeSpan` now covered by implicit cast for all but left operands

### Background
See #1354 (comment)

One issue is that the operator overloads only work when `TimeSpan` is the right operand.

I changed the code generation to take this into account, but another option would be to make a breaking change where we just don't support `TimeSpan` as the left operand at all.

Then users would have to cast explicitly, or for multiplication just reverse the operands.

This would affect 13 operators:

```
TimeSpan * Acceleration
TimeSpan * ElectricCurrent
TimeSpan * ElectricCurrentGradient
TimeSpan * ForceChangeRate
TimeSpan * KinematicViscosity
TimeSpan * MassFlow
TimeSpan * MolarFlow
TimeSpan * Power
TimeSpan * PressureChangeRate
TimeSpan * RotationalSpeed
TimeSpan * Speed
TimeSpan * TemperatureChangeRate
TimeSpan * VolumeFlow
```

Of which only 6 are used in tests so I assume are supported in v5:
```
TimeSpan * KinematicViscosity
TimeSpan * MassFlow
TimeSpan * Power
TimeSpan * RotationalSpeed
TimeSpan * TemperatureChangeRate
TimeSpan * Speed
```

---------

Co-authored-by: Andreas Gullberg Larsen <[email protected]>
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angularsen approved these changes Mar 1, 2024
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Looks good to me, just one minor comment we can address later.

@angularsen angularsen merged commit f7ce00b into angularsen:release/v6 Mar 1, 2024
angularsen added a commit to Tim-Borcherding/UnitsNet that referenced this pull request Mar 1, 2024
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Remove redundant
649a56a 
Division now inferred by f7ce00b - Inferred division from defined multiplication relations (angularsen#1354)
@angularsen angularsen mentioned this pull request Mar 1, 2024
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@Muximize Muximize deleted the inferred-division branch March 2, 2024 17:48
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angularsen commented Mar 3, 2024

Nuget on the way

Release UnitsNet/6.0.0-pre003 · angularsen/UnitsNet

@Muximize Muximize mentioned this pull request Jul 29, 2024
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