Unable to make DerivedUnits with Squared/Exponential Denominators

[jlambright]

I've tried to accomplish this in many ways, but they all fall flat on their face. I need to be able to create acceleration units. Are there any best practices?

[mongoose13]

Hi Josh, I'm terribly sorry you're having trouble. I'm currently in the Andes with very limited access to the Internet and anything related to Dart. I'll be able to help more closer to April when I get back, but in the meantime can you give some quick examples of what you have tried and what the failure is? I would expect that something like: final metersPerSecondSquared = DerivedUnit2(meters.per.second, seconds); (I don't have a computer in front of me, so I'm just doing this by memory, forgive me if I'm off on the syntax). Thanks, -Bruce

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On Thu, Mar 6, 2025, 11:07 Josh Lambright ***@***.***> wrote: I've tried to accomplish this in many ways, but they all fall flat on their face. I need to be able to create acceleration units. Are there any best practices? — Reply to this email directly, view it on GitHub <#6>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABNXFO2XGFF2YTLXL44ZMD2TBJAXAVCNFSM6AAAAABYOZDQ46VHI2DSMVQWIX3LMV43ASLTON2WKOZSHEYDANJRGUYDGMQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***> [image: jlambright]*jlambright* created an issue (mongoose13/fling-units#6) <#6> I've tried to accomplish this in many ways, but they all fall flat on their face. I need to be able to create acceleration units. Are there any best practices? — Reply to this email directly, view it on GitHub <#6>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABNXFO2XGFF2YTLXL44ZMD2TBJAXAVCNFSM6AAAAABYOZDQ46VHI2DSMVQWIX3LMV43ASLTON2WKOZSHEYDANJRGUYDGMQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[mongoose13]

Ah, I think you'll need to use one of the specialized constructors, as in: DerivedUnit2.quotient(...) Either way, I'd love to hear about your use case and how I can improve the library.

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On Tue, Mar 11, 2025, 19:31 Bruce Santier ***@***.***> wrote: Hi Josh, I'm terribly sorry you're having trouble. I'm currently in the Andes with very limited access to the Internet and anything related to Dart. I'll be able to help more closer to April when I get back, but in the meantime can you give some quick examples of what you have tried and what the failure is? I would expect that something like: final metersPerSecondSquared = DerivedUnit2(meters.per.second, seconds); (I don't have a computer in front of me, so I'm just doing this by memory, forgive me if I'm off on the syntax). Thanks, -Bruce On Thu, Mar 6, 2025, 11:07 Josh Lambright ***@***.***> wrote: > I've tried to accomplish this in many ways, but they all fall flat on > their face. I need to be able to create acceleration units. Are there any > best practices? > > — > Reply to this email directly, view it on GitHub > <#6>, or unsubscribe > <https://github.com/notifications/unsubscribe-auth/AABNXFO2XGFF2YTLXL44ZMD2TBJAXAVCNFSM6AAAAABYOZDQ46VHI2DSMVQWIX3LMV43ASLTON2WKOZSHEYDANJRGUYDGMQ> > . > You are receiving this because you are subscribed to this thread.Message > ID: ***@***.***> > [image: jlambright]*jlambright* created an issue > (mongoose13/fling-units#6) > <#6> > > I've tried to accomplish this in many ways, but they all fall flat on > their face. I need to be able to create acceleration units. Are there any > best practices? > > — > Reply to this email directly, view it on GitHub > <#6>, or unsubscribe > <https://github.com/notifications/unsubscribe-auth/AABNXFO2XGFF2YTLXL44ZMD2TBJAXAVCNFSM6AAAAABYOZDQ46VHI2DSMVQWIX3LMV43ASLTON2WKOZSHEYDANJRGUYDGMQ> > . > You are receiving this because you are subscribed to this thread.Message > ID: ***@***.***> >

[mongoose13]

OK, I'm back at a computer. You should ideally use the third-order constructor:

final metersPerSecond = DerivedUnit3<UnitNumerator<Distance>,
      UnitDenominator<Time>, UnitDenominator<Time>, Distance, Time, Time>.from(
    UnitNumerator<Distance>(meters),
    UnitDenominator(seconds),
    UnitDenominator(seconds),
  );

You can convert between any of these, i.e.:

final milesPerHourPerMinute = DerivedUnit3<UnitNumerator<Distance>,
      UnitDenominator<Time>, UnitDenominator<Time>, Distance, Time, Time>.from(
    UnitNumerator<Distance>(miles),
    UnitDenominator(hours),
    UnitDenominator(minutes),
  );

print(metersPerSecond(3.0).butAs(milesPerHourPerMinute).withPrecision(4));
// 402.6 mi⋅h⁻¹⋅min⁻¹

Let me know if you have issues with this.