On 2021-09-28, 21:03, "Gilles Sadowski" <gillese...@gmail.com> wrote:
Hi,
I've discovered that there is additional red tape I have to handle before I can
contribute.
Cheers
Erik Svensson
Hi.
FTR: https://issues.apache.org/jira/browse/MATH-1630
Gilles
Le lun. 6 sept. 2021 à 21:18, Gilles Sadowski <gillese...@gmail.com> a
écrit :
>
> Hi.
>
> Le lun. 6 sept. 2021 à 15:26, Erik Svensson <erik.svens...@nasdaq.com> a
écrit :
> >
> > On 2021-09-02, 18:11, "Gilles Sadowski" <gillese...@gmail.com> wrote:
> >
> > WARNING - External email; exercise caution.
> >
> > Le jeu. 2 sept. 2021 à 16:30, Erik Svensson
<erik.svens...@nasdaq.com> a écrit :
> > >
> > > Hi!
> > >
> > >
> > >
> > > I’ve implemented profiles, where you can choose to use either
AccurateMath or jlM and it works on j8.
> >
> > Can you provide a link to the code?
> >
> > https://github.com/perf-coder/commons-math/tree/math-profiles-j8-am
>
> Thanks.
>
> > My changes are all in org.apache.commons.math4.legacy.core
> > The MathProfile.java API might warrant some work.
> > The MathProfile static block will check for a property (currently
org.apache.commons.math.provider ) which can have JDK_MATH as optional value.
> > All other values will default to AM as math provider.
> > For java 8, the code builds just fine
>
> It should not, unless you've disabled "CheckStyle", "PMD", ... ;-)
>
> > and works as intended. For java versions > 8, it will not build since
AM doesn't implement all methods in StrictMath (or so the tests say anyway).
> >
> > NB that the code is not release-ready. I need to add doc:s.
>
> There is a feeling of things being upside down: You've moved all the
> "AccurateMath" code to a new "AccurateMathImpl" class (whereas the
> *implementation* was indeed the former).
>
> Then, the new "AccurateMath" now computes results that depend on
> the selected "profile", entailing that there is no accuracy guarantee!
>
> The "MathAPI" class conjures the idea of some "new" API (defined by
> this project) whereas the API is defined by the contents of the JDK's
> "Math" class.
>
> Allowing any application to globally change the implementation (through
> "MathProfile") seems quite unsafe.
>
>
> What about the following approach:
> ---CUT---
> public final class JdkMath {
> /** Property identifier. */
> private static final String PROPERTY_KEY =
> "org.apache.commons.math.jdkmath";
> /** max(x, y). */
> private static final DoubleBinaryOperator max;
> /** sin(x). */
> private static final DoubleUnaryOperator sin;
> /** random(). */
> private static final DoubleSupplier random;
>
> /** Available implementations of {@link Math} functions. */
> public enum Impl {
> /** {@link AccurateMath Commons Math}. */
> CM,
> /** {@link Math JDK}. */
> JDK
> }
>
> static {
> final String prop = System.getProperty(PROPERTY_KEY);
> final Impl impl = prop != null ?
> Impl.valueOf(prop) :
> Impl.CM;
>
> switch(impl) {
> case CM:
> max = AccurateMath::max;
> sin = AccurateMath::sin;
> random = AccurateMath::random;
> break;
>
> case JDK:
> max = Math::max;
> sin = Math::sin;
> random = Math::random;
> break;
>
> default:
> throw new IllegalStateException("Internal error"); //
> Should never happen.
> }
> }
>
> /**
> * @param x Number.
> * @param y Number.
> * @return max(x, y).
> */
> public static double max(double x,
> double y) {
> return max.applyAsDouble(x, y);
> }
>
> /**
> * @param x Number.
> * @return sin(x).
> */
> public static double sin(double x) {
> return sin.applyAsDouble(x);
> }
>
> /**
> * @return a random number between 0 and 1.
> */
> public static double random() {
> return random.getAsDouble();
> }
>
> // ...
> }
> ---CUT---
> ?
>
> Regards,
> Gilles
>
> >
> > Cheers
> > Erik Svensson
> > > Building on later versions of the jdk fails on the
AccurateMathTest.checkMissingAccurateMathClasses test (not surprise there).
> > >
> > > I can implement the missing methods using the same algorithms as
OpenJDK,
> >
> > Do you mean copying (Java?) code that is maintained somewhere else?
> >
> > > we can remove the test or maybe something else?
> >
> > Perhaps refactor the test using assumptions.[1]
> >
> > > The second alternative depends on if AccurateMath is going to
keep on being a drop-in replacement for jlM.
> >
> > "FastMath" was a rewrite of the functions defined in
"java.lang.Math"
> > as of Java 8.
> > Its usefulness was in the implementations being equally or more
> > accurate and sometimes faster (on Java 5).
> > As mentioned in another thread, we should know whether that's still
> > the case in environments where the upcoming version of CM could
> > potentially be used.
> >
> > >
> > > How do you guys want to play this?
> > >
> >
> > [1]
https://junit.org/junit5/docs/current/user-guide/#writing-tests-assumptions
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