Simultaneous computation of cosine and sine

[Joseph D. Darcy]

PS I've filed

     JDK-8376833: Add sincos method to math library
     https://bugs.openjdk.org/browse/JDK-8376833

to track this enhancement.

-Joe

On 1/30/2026 12:43 PM, Raffaello Giulietti wrote:
> Dear Yassine,
>
> you proposal would be a welcome addition.
>
> To contribute to the OpenJDK, you or your employer would need to sign the Oracle Contributor Agreement (OCA) [1].
> I recommend you read the first 2 or 3 sections of the OpenJDK Developers’ Guide [2] for the details before submitting any patch.
>
>
> HTH
> Raffaello Giulietti
>
> ----
>
> [1] https://oca.opensource.oracle.com
> [2] https://openjdk.org/guide
>
> ________________________________________
> From: core-libs-dev <core-libs-dev-retn at openjdk.org> on behalf of Yassine Damerdji <yassine.damerdji at uliege.be>
> Sent: Friday, January 30, 2026 18:21
> To: core-libs-dev at openjdk.org
> Subject: Simultaneous computation of cosine and sine
>
> Dear all,
>
> I am a scientist and a Java developer in the ESA/DPAC consortium (https://www.cosmos.esa.int/web/gaia/dpac).
>
> I downloaded FdLibm.java from the Open-JDK project, and I wrote a function which computes simultaneously the cosine and sine of an angle. Indeed, in science we very often need both of the cosine and the sine in our computations.
>
> I noticed that we can save 25% of the processing time compared to two separate calls to the cos and sin functions. The reason for this is that we won't repeat the common function they share.
>
> My local tests were missing the JDK '@stable' annotation, which optimizes a lot and is not possible to keep in my local tests.
>
> It would be great if we could include the new function in the official OpenJDK project.
>
> I attach my local version of FdLibm.java (without @stable annotations) including the class SinCos (line 2483).
>
> Many thanks in advance,
>
> Yassine
>
> PS : Mr Ivanov redirected me to this mailing list.