Hello.
Le sam. 4 avr. 2020 à 23:16, <aherb...@apache.org> a écrit :
>
> This is an automated email from the ASF dual-hosted git repository.
>
> aherbert pushed a commit to branch master
> in repository https://gitbox.apache.org/repos/asf/commons-numbers.git
>
> commit 08edae944e4abe7ec4b95a72d3791a9f39fb53c8
> Author: Alex Herbert <aherb...@apache.org>
> AuthorDate: Sat Apr 4 21:23:08 2020 +0100
>
> Remove a branch from equals tests with NaN.
>
> A bitwise OR of the booleans is true if either boolean is true. Since
> they are both already computed then the || operator short circuit (if
> first is true) cannot avoid having to compute the second boolean.
>
> This change converts 3 conditional evaluations to 2 conditional
> evaluations.
Is this measurable? Is the difference significant?
I'm not actually asking any benchmarking, but such changes
should be balanced with the resulting code reduced (IMO)
readability.
Best,
Gilles
> ---
> .../main/java/org/apache/commons/numbers/core/Precision.java | 12
> ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git
> a/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/Precision.java
>
> b/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/Precision.java
> index d60806d..4155b51 100644
> ---
> a/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/Precision.java
> +++
> b/commons-numbers-core/src/main/java/org/apache/commons/numbers/core/Precision.java
> @@ -177,7 +177,8 @@ public final class Precision {
> public static boolean equalsIncludingNaN(float x, float y) {
> final boolean xIsNan = Float.isNaN(x);
> final boolean yIsNan = Float.isNaN(y);
> - return xIsNan || yIsNan ?
> + // Combine the booleans with bitwise OR
> + return (xIsNan | yIsNan) ?
> !(xIsNan ^ yIsNan) :
> equals(x, y, 1);
> }
> @@ -274,7 +275,8 @@ public final class Precision {
> public static boolean equalsIncludingNaN(float x, float y, int maxUlps) {
> final boolean xIsNan = Float.isNaN(x);
> final boolean yIsNan = Float.isNaN(y);
> - return xIsNan || yIsNan ?
> + // Combine the booleans with bitwise OR
> + return (xIsNan | yIsNan) ?
> !(xIsNan ^ yIsNan) :
> equals(x, y, maxUlps);
> }
> @@ -302,7 +304,8 @@ public final class Precision {
> public static boolean equalsIncludingNaN(double x, double y) {
> final boolean xIsNan = Double.isNaN(x);
> final boolean yIsNan = Double.isNaN(y);
> - return xIsNan || yIsNan ?
> + // Combine the booleans with bitwise OR
> + return (xIsNan | yIsNan) ?
> !(xIsNan ^ yIsNan) :
> equals(x, y, 1);
> }
> @@ -428,7 +431,8 @@ public final class Precision {
> public static boolean equalsIncludingNaN(double x, double y, int
> maxUlps) {
> final boolean xIsNan = Double.isNaN(x);
> final boolean yIsNan = Double.isNaN(y);
> - return xIsNan || yIsNan ?
> + // Combine the booleans with bitwise OR
> + return (xIsNan | yIsNan) ?
> !(xIsNan ^ yIsNan) :
> equals(x, y, maxUlps);
> }
>
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