Inferred division from defined multiplication relations

CodeGen/Generators/QuantityRelationsParser.cs

@@ -25,13 +25,16 @@ internal static class QuantityRelationsParser
  ///
  /// The format of a relation definition is "Quantity.Unit operator Quantity.Unit = Quantity.Unit" (See examples below).
  /// "double" can be used as a unitless operand.
- /// "1" can be used as the left operand to define inverse relations.
+ /// "1" can be used as the result operand to define inverse relations.
+ ///
+ /// Division relations are inferred from multiplication relations,
+ /// but this can be skipped if the string ends with "NoInferredDivision".
  /// </summary>
  /// <example>
  /// [
- ///  "Power.Watt = ElectricPotential.Volt * ElectricCurrent.Ampere",
- ///  "Speed.MeterPerSecond = Length.Meter / Duration.Second",
- ///  "ReciprocalLength.InverseMeter = 1 / Length.Meter"
+ /// "1 = Length.Meter * ReciprocalLength.InverseMeter"
+ /// "Power.Watt = ElectricPotential.Volt * ElectricCurrent.Ampere",
+ /// "Mass.Kilogram = MassConcentration.KilogramPerCubicMeter * Volume.CubicMeter -- NoInferredDivision",
  /// ]
  /// </example>
  /// <param name="rootDir">Repository root directory.</param>
@@ -58,10 +61,25 @@ public static void ParseAndApplyRelations(string rootDir, Quantity[] quantities)
  RightUnit = r.LeftUnit,
  })
  .ToList());
+
+ // We can infer division relations from multiplication relations.
+ relations.AddRange(relations
+ .Where(r => r is { Operator: "*", NoInferredDivision: false })
+ .Select(r => r with
+ {
+ Operator = "/",
+ LeftQuantity = r.ResultQuantity,
+ LeftUnit = r.ResultUnit,
+ ResultQuantity = r.LeftQuantity,
+ ResultUnit = r.LeftUnit,
+ })
+ // Skip division between equal quantities because the ratio is already generated as part of the Arithmetic Operators.
+ .Where(r => r.LeftQuantity != r.RightQuantity)
+ .ToList());
 
  // Sort all relations to keep generated operators in a consistent order.
  relations.Sort();
- 
+
  var duplicates = relations
  .GroupBy(r => r.SortString)
  .Where(g => g.Count() > 1)
@@ -73,6 +91,18 @@ public static void ParseAndApplyRelations(string rootDir, Quantity[] quantities)
  var list = string.Join("\n ", duplicates);
  throw new UnitsNetCodeGenException($"Duplicate inferred relations:\n {list}");
  }
+
+ var ambiguous = relations
+ .GroupBy(r => $"{r.LeftQuantity.Name} {r.Operator} {r.RightQuantity.Name}")
+ .Where(g => g.Count() > 1)
+ .Select(g => g.Key)
+ .ToList();
+
+ if (ambiguous.Any())
+ {
+ var list = string.Join("\n ", ambiguous);
+ throw new UnitsNetCodeGenException($"Ambiguous inferred relations:\n {list}\n\nHint: you could use NoInferredDivision in the definition file.");
+ }
 
  foreach (var quantity in quantities)
  {
@@ -122,7 +152,7 @@ private static QuantityRelation ParseRelation(string relationString, IReadOnlyDi
  {
  var segments = relationString.Split(' ');
 
- if (segments is not [_, "=", _, "*" or "/", _])
+ if (segments is not [_, "=", _, "*", _, ..])
  {
  throw new Exception($"Invalid relation string: {relationString}");
  }
@@ -140,15 +170,14 @@ private static QuantityRelation ParseRelation(string relationString, IReadOnlyDi
  var rightUnit = GetUnit(rightQuantity, right.ElementAtOrDefault(1));
  var resultUnit = GetUnit(resultQuantity, result.ElementAtOrDefault(1));
 
- if (leftQuantity.Name == "1")
+ if (resultQuantity.Name == "1")
  {
  @operator = "inverse";
- leftQuantity = resultQuantity;
- leftUnit = resultUnit;
  }
 
  return new QuantityRelation
  {
+ NoInferredDivision = segments.Contains("NoInferredDivision"),
  Operator = @operator,
  LeftQuantity = leftQuantity,
  LeftUnit = leftUnit,

CodeGen/JsonTypes/QuantityRelation.cs

@@ -7,6 +7,7 @@ namespace CodeGen.JsonTypes
 {
  internal record QuantityRelation : IComparable<QuantityRelation>
  {
+ public bool NoInferredDivision = false;
  public string Operator = null!;
 
  public Quantity LeftQuantity = null!;

Common/UnitRelations.json

@@ -1,164 +1,79 @@
 [
- "Acceleration.MeterPerSecondSquared = Force.Newton / Mass.Kilogram",
- "Acceleration.MeterPerSecondSquared = SpecificWeight.NewtonPerCubicMeter / Density.KilogramPerCubicMeter",
- "Acceleration.MeterPerSecondSquared = Speed.MeterPerSecond / Duration.Second",
+ "1 = Area.SquareMeter * ReciprocalArea.InverseSquareMeter",
+ "1 = ElectricResistivity.OhmMeter * ElectricConductivity.SiemensPerMeter",
+ "1 = Length.Meter * ReciprocalLength.InverseMeter",
+ "Acceleration.MeterPerSecondSquared = Jerk.MeterPerSecondCubed * Duration.Second",
  "AmountOfSubstance.Kilomole = MolarFlow.KilomolePerSecond * Duration.Second",
- "AmountOfSubstance.Mole = Mass.Kilogram / MolarMass.KilogramPerMole",
+ "AmountOfSubstance.Mole = Molarity.MolePerCubicMeter * Volume.CubicMeter",
  "Angle.Radian = RotationalSpeed.RadianPerSecond * Duration.Second",
- "Angle.Radian = Torque.NewtonMeter / RotationalStiffness.NewtonMeterPerRadian",
  "Area.SquareMeter = KinematicViscosity.SquareMeterPerSecond * Duration.Second",
  "Area.SquareMeter = Length.Meter * Length.Meter",
- "Area.SquareMeter = LinearDensity.KilogramPerMeter / Density.KilogramPerCubicMeter",
- "Area.SquareMeter = LuminousIntensity.Candela / Luminance.CandelaPerSquareMeter",
- "Area.SquareMeter = Mass.Kilogram / AreaDensity.KilogramPerSquareMeter",
- "Area.SquareMeter = MassFlow.KilogramPerSecond / MassFlux.KilogramPerSecondPerSquareMeter",
- "Area.SquareMeter = Power.Watt / HeatFlux.WattPerSquareMeter",
- "Area.SquareMeter = Volume.CubicMeter / Length.Meter",
- "Area.SquareMeter = VolumeFlow.CubicMeterPerSecond / Speed.MeterPerSecond",
- "AreaDensity.KilogramPerSquareMeter = Mass.Kilogram / Area.SquareMeter",
- "BrakeSpecificFuelConsumption.KilogramPerJoule = double / SpecificEnergy.JoulePerKilogram",
- "BrakeSpecificFuelConsumption.KilogramPerJoule = MassFlow.KilogramPerSecond / Power.Watt",
- "Density.KilogramPerCubicMeter = double / SpecificVolume.CubicMeterPerKilogram",
- "Density.KilogramPerCubicMeter = LinearDensity.KilogramPerMeter / Area.SquareMeter",
- "Density.KilogramPerCubicMeter = Mass.Kilogram / Volume.CubicMeter",
- "Density.KilogramPerCubicMeter = MassFlow.KilogramPerSecond / VolumeFlow.CubicMeterPerSecond",
- "Density.KilogramPerCubicMeter = MassFlux.KilogramPerSecondPerSquareMeter / Speed.MeterPerSecond",
- "Density.KilogramPerCubicMeter = SpecificWeight.NewtonPerCubicMeter / Acceleration.MeterPerSecondSquared",
+ "AreaMomentOfInertia.MeterToTheFourth = Volume.CubicMeter * Length.Meter",
+ "double = Density.KilogramPerCubicMeter * SpecificVolume.CubicMeterPerKilogram",
  "double = SpecificEnergy.JoulePerKilogram * BrakeSpecificFuelConsumption.KilogramPerJoule",
  "double = TemperatureDelta.Kelvin * CoefficientOfThermalExpansion.PerKelvin",
- "Duration.Hour = ElectricCharge.AmpereHour / ElectricCurrent.Ampere",
- "Duration.Second = Energy.Joule / Power.Watt",
- "Duration.Second = Force.Newton / ForceChangeRate.NewtonPerSecond",
- "Duration.Second = Length.Meter / Speed.MeterPerSecond",
- "Duration.Second = Speed.MeterPerSecond / Acceleration.MeterPerSecondSquared",
  "DynamicViscosity.NewtonSecondPerMeterSquared = Density.KilogramPerCubicMeter * KinematicViscosity.SquareMeterPerSecond",
  "ElectricCharge.AmpereHour = ElectricCurrent.Ampere * Duration.Hour",
- "ElectricCharge.Coulomb = Energy.Joule / ElectricPotential.Volt",
- "ElectricConductivity.SiemensPerMeter = 1 / ElectricResistivity.OhmMeter",
- "ElectricCurrent.Ampere = ElectricCharge.AmpereHour / Duration.Hour",
  "ElectricCurrent.Ampere = ElectricCurrentGradient.AmperePerSecond * Duration.Second",
- "ElectricCurrent.Ampere = ElectricPotential.Volt / ElectricResistance.Ohm",
- "ElectricCurrent.Ampere = Power.Watt / ElectricPotential.Volt",
- "ElectricCurrentGradient.AmperePerSecond = ElectricCurrent.Ampere / Duration.Second",
  "ElectricPotential.Volt = ElectricCurrent.Ampere * ElectricResistance.Ohm",
- "ElectricPotential.Volt = Energy.Joule / ElectricCharge.Coulomb",
- "ElectricPotential.Volt = Power.Watt / ElectricCurrent.Ampere",
- "ElectricResistance.Ohm = ElectricPotential.Volt / ElectricCurrent.Ampere",
  "Energy.Joule = ElectricPotential.Volt * ElectricCharge.Coulomb",
  "Energy.Joule = EnergyDensity.JoulePerCubicMeter * Volume.CubicMeter",
  "Energy.Joule = Power.Watt * Duration.Second",
  "Energy.Joule = SpecificEnergy.JoulePerKilogram * Mass.Kilogram",
  "Energy.Joule = TemperatureDelta.Kelvin * Entropy.JoulePerKelvin",
- "Entropy.JoulePerKelvin = Energy.Joule / TemperatureDelta.Kelvin",
  "Entropy.JoulePerKelvin = SpecificEntropy.JoulePerKilogramKelvin * Mass.Kilogram",
  "Force.Newton = ForceChangeRate.NewtonPerSecond * Duration.Second",
  "Force.Newton = ForcePerLength.NewtonPerMeter * Length.Meter",
- "Force.Newton = ForcePerLength.NewtonPerMeter / ReciprocalLength.InverseMeter",
  "Force.Newton = Mass.Kilogram * Acceleration.MeterPerSecondSquared",
- "Force.Newton = Power.Watt / Speed.MeterPerSecond",
  "Force.Newton = Pressure.Pascal * Area.SquareMeter",
- "Force.Newton = Pressure.Pascal / ReciprocalArea.InverseSquareMeter",
- "Force.Newton = Torque.NewtonMeter / Length.Meter",
  "ForcePerLength.NewtonPerMeter = Force.Newton * ReciprocalLength.InverseMeter",
- "ForcePerLength.NewtonPerMeter = Force.Newton / Length.Meter",
- "ForcePerLength.NewtonPerMeter = Pressure.Pascal / ReciprocalLength.InverseMeter",
+ "ForcePerLength.NewtonPerMeter = Pressure.NewtonPerSquareMeter * Length.Meter",
  "ForcePerLength.NewtonPerMeter = SpecificWeight.NewtonPerCubicMeter * Area.SquareMeter",
- "HeatFlux.WattPerSquareMeter = Power.Watt / Area.SquareMeter",
- "Jerk.MeterPerSecondCubed = Acceleration.MeterPerSecondSquared / Duration.Second",
- "KinematicViscosity.SquareMeterPerSecond = DynamicViscosity.NewtonSecondPerMeterSquared / Density.KilogramPerCubicMeter",
  "KinematicViscosity.SquareMeterPerSecond = Length.Meter * Speed.MeterPerSecond",
- "Length.Kilometer = TemperatureDelta.Kelvin / TemperatureGradient.DegreeCelsiusPerKilometer",
- "Length.Meter = Area.SquareMeter / Length.Meter",
- "Length.Meter = Force.Newton / ForcePerLength.NewtonPerMeter",
- "Length.Meter = Mass.Kilogram / LinearDensity.KilogramPerMeter",
- "Length.Meter = Pressure.Pascal / SpecificWeight.NewtonPerCubicMeter",
- "Length.Meter = ReciprocalLength.InverseMeter / ReciprocalArea.InverseSquareMeter",
- "Length.Meter = RotationalStiffness.NewtonMeterPerRadian / RotationalStiffnessPerLength.NewtonMeterPerRadianPerMeter",
  "Length.Meter = Speed.MeterPerSecond * Duration.Second",
- "Length.Meter = Torque.NewtonMeter / Force.Newton",
- "Length.Meter = Volume.CubicMeter / Area.SquareMeter",
  "LinearDensity.KilogramPerMeter = Area.SquareMeter * Density.KilogramPerCubicMeter",
- "LinearDensity.KilogramPerMeter = Mass.Kilogram / Length.Meter",
- "Luminance.CandelaPerSquareMeter = LuminousIntensity.Candela / Area.SquareMeter",
  "LuminousIntensity.Candela = Luminance.CandelaPerSquareMeter * Area.SquareMeter",
  "Mass.Gram = AmountOfSubstance.Mole * MolarMass.GramPerMole",
  "Mass.Kilogram = AreaDensity.KilogramPerSquareMeter * Area.SquareMeter",
  "Mass.Kilogram = Density.KilogramPerCubicMeter * Volume.CubicMeter",
- "Mass.Kilogram = Energy.Joule / SpecificEnergy.JoulePerKilogram",
- "Mass.Kilogram = Force.Newton / Acceleration.MeterPerSecondSquared",
  "Mass.Kilogram = LinearDensity.KilogramPerMeter * Length.Meter",
- "Mass.Kilogram = Mass.Kilogram / MassFraction.DecimalFraction",
- "Mass.Kilogram = MassConcentration.KilogramPerCubicMeter * Volume.CubicMeter",
+ "Mass.Kilogram = MassConcentration.KilogramPerCubicMeter * Volume.CubicMeter -- NoInferredDivision",
  "Mass.Kilogram = MassFlow.KilogramPerSecond * Duration.Second",
  "Mass.Kilogram = MassFraction.DecimalFraction * Mass.Kilogram",
- "MassConcentration.GramPerCubicMeter = Molarity.MolePerCubicMeter * MolarMass.GramPerMole",
+ "MassConcentration.KilogramPerCubicMeter = Molarity.MolePerCubicMeter * MolarMass.KilogramPerMole",
  "MassConcentration.KilogramPerCubicMeter = VolumeConcentration.DecimalFraction * Density.KilogramPerCubicMeter",
- "MassFlow.GramPerSecond = Area.SquareMeter * MassFlux.GramPerSecondPerSquareMeter",
- "MassFlow.KilogramPerSecond = Mass.Kilogram / Duration.Second",
+ "MassFlow.KilogramPerSecond = Area.SquareMeter * MassFlux.KilogramPerSecondPerSquareMeter",
  "MassFlow.KilogramPerSecond = MolarFlow.KilomolePerSecond * MolarMass.KilogramPerKilomole",
  "MassFlow.KilogramPerSecond = Power.Watt * BrakeSpecificFuelConsumption.KilogramPerJoule",
- "MassFlow.KilogramPerSecond = Power.Watt / SpecificEnergy.JoulePerKilogram",
  "MassFlow.KilogramPerSecond = VolumeFlow.CubicMeterPerSecond * Density.KilogramPerCubicMeter",
- "MassFlux.KilogramPerSecondPerSquareMeter = MassFlow.KilogramPerSecond / Area.SquareMeter",
  "MassFlux.KilogramPerSecondPerSquareMeter = Speed.MeterPerSecond * Density.KilogramPerCubicMeter",
- "Molarity.MolePerCubicMeter = AmountOfSubstance.Mole / Volume.CubicMeter",
- "Molarity.MolePerCubicMeter = MassConcentration.GramPerCubicMeter / MolarMass.GramPerMole",
+ "MolarFlow.MolePerSecond = VolumeFlow.CubicMeterPerSecond * Molarity.MolePerCubicMeter",
  "Molarity.MolePerCubicMeter = Molarity.MolePerCubicMeter * VolumeConcentration.DecimalFraction",
  "Power.Watt = ElectricPotential.Volt * ElectricCurrent.Ampere",
  "Power.Watt = Energy.Joule * Frequency.PerSecond",
- "Power.Watt = Energy.Joule / Duration.Second",
  "Power.Watt = Force.Newton * Speed.MeterPerSecond",
  "Power.Watt = HeatFlux.WattPerSquareMeter * Area.SquareMeter",
- "Power.Watt = MassFlow.KilogramPerSecond / BrakeSpecificFuelConsumption.KilogramPerJoule",
  "Power.Watt = SpecificEnergy.JoulePerKilogram * MassFlow.KilogramPerSecond",
+ "Power.Watt = Torque.NewtonMeter * RotationalSpeed.RadianPerSecond",
  "Pressure.NewtonPerSquareMeter = Force.Newton * ReciprocalArea.InverseSquareMeter",
  "Pressure.NewtonPerSquareMeter = ForcePerLength.NewtonPerMeter * ReciprocalLength.InverseMeter",
- "Pressure.NewtonPerSquareMeter = ForcePerLength.NewtonPerMeter / Length.Meter",
- "Pressure.Pascal = Force.Newton / Area.SquareMeter",
  "Pressure.Pascal = PressureChangeRate.PascalPerSecond * Duration.Second",
  "Pressure.Pascal = SpecificWeight.NewtonPerCubicMeter * Length.Meter",
- "PressureChangeRate.PascalPerSecond = Pressure.Pascal / Duration.Second",
  "Ratio.DecimalFraction = Area.SquareMeter * ReciprocalArea.InverseSquareMeter",
- "ReciprocalArea.InverseSquareMeter = 1 / Area.SquareMeter",
  "ReciprocalArea.InverseSquareMeter = ReciprocalLength.InverseMeter * ReciprocalLength.InverseMeter",
- "ReciprocalLength.InverseMeter = 1 / Length.Meter",
- "ReciprocalLength.InverseMeter = ReciprocalArea.InverseSquareMeter / ReciprocalLength.InverseMeter",
- "RotationalSpeed.RadianPerSecond = Angle.Radian / Duration.Second",
- "RotationalSpeed.RadianPerSecond = Power.Watt / Torque.NewtonMeter",
+ "ReciprocalLength.InverseMeter = Length.Meter * ReciprocalArea.InverseSquareMeter",
  "RotationalStiffness.NewtonMeterPerRadian = RotationalStiffnessPerLength.NewtonMeterPerRadianPerMeter * Length.Meter",
- "RotationalStiffness.NewtonMeterPerRadian = Torque.NewtonMeter / Angle.Radian",
- "RotationalStiffnessPerLength.NewtonMeterPerRadianPerMeter = RotationalStiffness.NewtonMeterPerRadian / Length.Meter",
- "SpecificEnergy.JoulePerKilogram = double / BrakeSpecificFuelConsumption.KilogramPerJoule",
- "SpecificEnergy.JoulePerKilogram = Energy.Joule / Mass.Kilogram",
- "SpecificEnergy.JoulePerKilogram = Power.Watt / MassFlow.KilogramPerSecond",
  "SpecificEnergy.JoulePerKilogram = SpecificEntropy.JoulePerKilogramKelvin * TemperatureDelta.Kelvin",
  "SpecificEnergy.JoulePerKilogram = Speed.MeterPerSecond * Speed.MeterPerSecond",
- "SpecificEntropy.JoulePerKilogramKelvin = Entropy.JoulePerKelvin / Mass.Kilogram",
- "SpecificEntropy.JoulePerKilogramKelvin = SpecificEnergy.JoulePerKilogram / TemperatureDelta.Kelvin",
  "SpecificWeight.NewtonPerCubicMeter = Acceleration.MeterPerSecondSquared * Density.KilogramPerCubicMeter",
- "SpecificWeight.NewtonPerCubicMeter = Pressure.Pascal / Length.Meter",
  "Speed.MeterPerSecond = Acceleration.MeterPerSecondSquared * Duration.Second",
- "Speed.MeterPerSecond = KinematicViscosity.SquareMeterPerSecond / Length.Meter",
- "Speed.MeterPerSecond = Length.Meter / Duration.Second",
- "Speed.MeterPerSecond = MassFlux.KilogramPerSecondPerSquareMeter / Density.KilogramPerCubicMeter",
- "Speed.MeterPerSecond = VolumeFlow.CubicMeterPerSecond / Area.SquareMeter",
  "TemperatureDelta.DegreeCelsius = TemperatureChangeRate.DegreeCelsiusPerSecond * Duration.Second",
  "TemperatureDelta.DegreeCelsius = TemperatureGradient.DegreeCelsiusPerKilometer * Length.Kilometer",
- "TemperatureDelta.Kelvin = Energy.Joule / Entropy.JoulePerKelvin",
- "TemperatureGradient.KelvinPerMeter = TemperatureDelta.Kelvin / Length.Meter",
  "Torque.NewtonMeter = ForcePerLength.NewtonPerMeter * Area.SquareMeter",
  "Torque.NewtonMeter = Length.Meter * Force.Newton",
- "Torque.NewtonMeter = Power.Watt / RotationalSpeed.RadianPerSecond",
  "Torque.NewtonMeter = RotationalStiffness.NewtonMeterPerRadian * Angle.Radian",
- "Volume.CubicMeter = AmountOfSubstance.Mole / Molarity.MolePerCubicMeter",
- "Volume.CubicMeter = AreaMomentOfInertia.MeterToTheFourth / Length.Meter",
  "Volume.CubicMeter = Length.Meter * Area.SquareMeter",
- "Volume.CubicMeter = Mass.Kilogram / Density.KilogramPerCubicMeter",
  "Volume.CubicMeter = SpecificVolume.CubicMeterPerKilogram * Mass.Kilogram",
  "Volume.CubicMeter = VolumeFlow.CubicMeterPerSecond * Duration.Second",
- "VolumeConcentration.DecimalFraction = MassConcentration.KilogramPerCubicMeter / Density.KilogramPerCubicMeter",
- "VolumeFlow.CubicMeterPerSecond = Area.SquareMeter * Speed.MeterPerSecond",
- "VolumeFlow.CubicMeterPerSecond = MassFlow.KilogramPerSecond / Density.KilogramPerCubicMeter",
- "VolumeFlow.CubicMeterPerSecond = MolarFlow.MolePerSecond / Molarity.MolePerCubicMeter",
- "VolumeFlow.CubicMeterPerSecond = Volume.CubicMeter / Duration.Second"
+ "VolumeFlow.CubicMeterPerSecond = Area.SquareMeter * Speed.MeterPerSecond"
 ]

UnitsNet.Tests/CustomCode/VolumeTests.cs

@@ -151,8 +151,8 @@ public void VolumeDividedByDurationEqualsVolumeFlow()
  [Fact]
  public void VolumeDividedByVolumeFlowEqualsTimeSpan()
  {
- TimeSpan timeSpan = Volume.FromCubicMeters(20) / VolumeFlow.FromCubicMetersPerSecond(2);
- Assert.Equal(TimeSpan.FromSeconds(10), timeSpan);
+ Duration duration = Volume.FromCubicMeters(20) / VolumeFlow.FromCubicMetersPerSecond(2);
+ Assert.Equal(Duration.FromSeconds(10), duration);
  }
  }
 }