Double
Orderings forDoubles.
The behavior of the comparison operations provided by the default (implicit) ordering onDouble changed in 2.10.0 and 2.13.0. Prior to Scala 2.10.0, theOrdering instance used semantics consistent withjava.lang.Double.compare.
Scala 2.10.0 changed the implementation oflt,equiv,min, etc., to be IEEE 754 compliant, while keeping thecompare method NOT compliant, creating an internally inconsistent instance. IEEE 754 specifies that0.0 == -0.0. In addition, it requires all comparisons withDouble.NaN returnfalse thus0.0 < Double.NaN,0.0 > Double.NaN, andDouble.NaN == Double.NaN all yieldfalse, analogousNone inflatMap.
Recognizing the limitation of the IEEE 754 semantics in terms of ordering, Scala 2.13.0 created two instances:Ordering.Double.IeeeOrdering, which retains the IEEE 754 semantics from Scala 2.12.x, andOrdering.Double.TotalOrdering, which brings back thejava.lang.Double.compare semantics for all operations. The default extendsTotalOrdering.
List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).sorted // List(-Infinity, 0.0, 1.0, NaN)List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).min // -Infinityimplicitly[Ordering[Double]].lt(0.0, 0.0 / 0.0) // true{ import Ordering.Double.IeeeOrdering List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).sorted // List(-Infinity, 0.0, 1.0, NaN) List(0.0, 1.0, 0.0 / 0.0, -1.0 / 0.0).min // NaN implicitly[Ordering[Double]].lt(0.0, 0.0 / 0.0) // false}Attributes
- Source
- Ordering.scala
- Graph
- Supertypes
- Self type
- Double.type
Members list
Type members
Classlikes
Attributes
- Companion
- trait
- Source
- Ordering.scala
- Supertypes
- traitIeeeOrderingtraitPartialOrdering[Double]traitSerializabletraitComparator[Double]classObjecttraitMatchableclassAnyShow all
- Self type
- IeeeOrdering.type
An ordering forDoubles which is consistent with IEEE specifications whenever possible.
An ordering forDoubles which is consistent with IEEE specifications whenever possible.
lt,lteq,equiv,gteqandgtare consistent with primitive comparison operations forDoubles, and returnfalsewhen called withNaN.minandmaxare consistent withmath.minandmath.max, and returnNaNwhen called withNaNas either argument.comparebehaves the same asjava.lang.Double.compare.
Because the behavior ofDoubles specified by IEEE is not consistent with a total ordering when dealing withNaN, there are two orderings defined forDouble:TotalOrdering, which is consistent with a total ordering, andIeeeOrdering, which is consistent as much as possible with IEEE spec and floating point operations defined inscala.math.
This ordering may be preferable for numeric contexts.
Attributes
- See also
- Companion
- object
- Source
- Ordering.scala
- Supertypes
- traitPartialOrdering[Double]traitSerializabletraitComparator[Double]classObjecttraitMatchableclassAnyShow all
- Known subtypes
- objectDoubleIsFractionalobjectIeeeOrdering
Attributes
- Companion
- trait
- Source
- Ordering.scala
- Supertypes
- traitTotalOrderingtraitPartialOrdering[Double]traitSerializabletraitComparator[Double]classObjecttraitMatchableclassAnyShow all
- Self type
- TotalOrdering.type
An ordering forDoubles which is a fully consistent total ordering, and treatsNaN as larger than all otherDouble values; it behaves the same asjava.lang.Double.compare.
An ordering forDoubles which is a fully consistent total ordering, and treatsNaN as larger than all otherDouble values; it behaves the same asjava.lang.Double.compare.
Because the behavior ofDoubles specified by IEEE is not consistent with a total ordering when dealing withNaN, there are two orderings defined forDouble:TotalOrdering, which is consistent with a total ordering, andIeeeOrdering, which is consistent as much as possible with IEEE spec and floating point operations defined inscala.math.
This ordering may be preferable for sorting collections.
Attributes
- See also
- Companion
- object
- Source
- Ordering.scala
- Supertypes
- traitPartialOrdering[Double]traitSerializabletraitComparator[Double]classObjecttraitMatchableclassAnyShow all
- Known subtypes
- objectDeprecatedDoubleOrderingobjectTotalOrdering