Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
On Thu, 2 Jun 2022 08:22:11 GMT, Raffaello Giulietti
wrote:
>> src/java.base/share/classes/java/lang/Math.java line 823:
>>
>>> 821: * @apiNote
>>> 822: * This method corresponds to the convertTowardPositive operation
>>> 823: * defined in IEEE 754.
>>
>> Probably what is meant is IEEE `convertToIntegerTowardPositive` (not
>> `convertTowardPositive`).
>> However, that's another kind of rounding, which always rounds any
>> non-integral value toward positive infinity, not just ties. This is not what
>> happens with this method.
>
>> not just ties
> Plz. disregard this 3 words
Okay, checking the IEEE 754-2019 spec again, there are operations to round a
floating-point value to an integral-valued floating-point value
(roundToIntegral{$ROUNDING_DIRECTION_ATTRIBUTE} and separately operations to
round from a floating-point value to a value in an integer format
(convertToInteger{$ROUNDING_DIRECTION_ATTRIBUTE} ). However, as noted, there is
no IEEE 754 operations for rounding up only for ties. I'll remove the API notes
for the round methods; thanks for catching this.
-
PR: https://git.openjdk.java.net/jdk/pull/8876
Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
On Wed, 1 Jun 2022 08:39:44 GMT, Raffaello Giulietti wrote: > not just ties Plz. disregard this 3 words - PR: https://git.openjdk.java.net/jdk/pull/8876
Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
On Wed, 1 Jun 2022 02:05:40 GMT, Joe Darcy wrote: >> Generally add apiNote's to map from Java library methods to particular IEEE >> 754 operations. For now, I only added such notes to java.lang.Math and not >> java.lang.StrictMath. > > Joe Darcy has updated the pull request with a new target base due to a merge > or a rebase. The incremental webrev excludes the unrelated changes brought in > by the merge/rebase. The pull request contains four additional commits since > the last revision: > > - Respond to review feedback; make another pass to link methods to IEEE 754 > operations. > - Merge branch 'master' into JDK-8273346 > - Add floor and ceil. > - JDK-8273346: Examine use of "rounding mode" and "rounding policy" in Math > and StrictMath src/java.base/share/classes/java/lang/Math.java line 823: > 821: * @apiNote > 822: * This method corresponds to the convertTowardPositive operation > 823: * defined in IEEE 754. Probably what is meant is IEEE `convertToIntegerTowardPositive` (not `convertTowardPositive`). However, that's another kind of rounding, which always rounds any non-integral value toward positive infinity, not just ties. This is not what happens with this method. - PR: https://git.openjdk.java.net/jdk/pull/8876
Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
On Wed, 25 May 2022 08:56:27 GMT, Raffaello Giulietti
wrote:
>> Joe Darcy has updated the pull request with a new target base due to a merge
>> or a rebase. The incremental webrev excludes the unrelated changes brought
>> in by the merge/rebase. The pull request contains four additional commits
>> since the last revision:
>>
>> - Respond to review feedback; make another pass to link methods to IEEE 754
>> operations.
>> - Merge branch 'master' into JDK-8273346
>> - Add floor and ceil.
>> - JDK-8273346: Examine use of "rounding mode" and "rounding policy" in Math
>> and StrictMath
>
> src/java.base/share/classes/java/lang/Math.java line 771:
>
>> 769: * This method corresponds to the convertToIntegerTiesToEven
>> 770: * operation defined in IEEE 754.
>> 771: *
>
> IEEE `convertToIntegerTiesToEven` rounds ties to the even integer.
> The method's spec, however, requires ties to round toward positive infinity.
> Unfortunately, IEEE 754 doesn't offer a `convertToIntegerTiesToPositive`
Good catch; found a different 754 operation that seems to fit.
> src/java.base/share/classes/java/math/RoundingMode.java line 49:
>
>> 47: * exponent range of {@code BigDecimal}, the mathematical result will
>> 48: * be exactly representable in the result precision or fall between
>> 49: * two representable values. In the case of falling between two
>
> Perhaps better would be
> `two adjacent representable values.`
Agreed; adjusted in subsequent push.
-
PR: https://git.openjdk.java.net/jdk/pull/8876
Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
On Wed, 1 Jun 2022 02:05:40 GMT, Joe Darcy wrote: >> Generally add apiNote's to map from Java library methods to particular IEEE >> 754 operations. For now, I only added such notes to java.lang.Math and not >> java.lang.StrictMath. > > Joe Darcy has updated the pull request with a new target base due to a merge > or a rebase. The incremental webrev excludes the unrelated changes brought in > by the merge/rebase. The pull request contains four additional commits since > the last revision: > > - Respond to review feedback; make another pass to link methods to IEEE 754 > operations. > - Merge branch 'master' into JDK-8273346 > - Add floor and ceil. > - JDK-8273346: Examine use of "rounding mode" and "rounding policy" in Math > and StrictMath I look another pass over the methods in Float, Double, and Math for opportunities to link to IEEE 754 operations. At least for now, I choose not to link to abs since IEEE 754 abs can have different behavior for NaN values that java.lang.Math.abs. If a link is made, this difference would need to be noted. - PR: https://git.openjdk.java.net/jdk/pull/8876
Re: RFR: 8273346: Expand library mappings to IEEE 754 operations [v2]
> Generally add apiNote's to map from Java library methods to particular IEEE > 754 operations. For now, I only added such notes to java.lang.Math and not > java.lang.StrictMath. Joe Darcy has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision: - Respond to review feedback; make another pass to link methods to IEEE 754 operations. - Merge branch 'master' into JDK-8273346 - Add floor and ceil. - JDK-8273346: Examine use of "rounding mode" and "rounding policy" in Math and StrictMath - Changes: - all: https://git.openjdk.java.net/jdk/pull/8876/files - new: https://git.openjdk.java.net/jdk/pull/8876/files/050e6ecd..9169ad9e Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk=8876=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk=8876=00-01 Stats: 46471 lines in 566 files changed: 22606 ins; 17922 del; 5943 mod Patch: https://git.openjdk.java.net/jdk/pull/8876.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8876/head:pull/8876 PR: https://git.openjdk.java.net/jdk/pull/8876
