Hello, I am working on a port of DragonBox to Java. If there is interest in contributing this is most welcome.
Suminda On Fri, 5 Feb 2021 at 21:51, Raffaello Giulietti < raffaello.giulie...@gmail.com> wrote: > Hello, > > as a reminder, a Java implementation of Schubfach [1] intended to > replace the current slow and expensive OpenJDK (Double|Float)::toString > algorithm has been discussed, presented and contributed to this mailing > list in several posts. The last implementation is available in pre-Skara > webrev form, as referenced in [2]. On my laptop hardware, the speedup > factor is 17.7x wrt OpenJDK. > > > > Recently, Alexander Bolz translated Schubfach to C++ for the purpose of > comparing the performance of several bin2dec floating-point numbers > algorithms [3]. > > In the meantime, Junekey Jeon implemented and perfected his own > Dragonbox in C++, a new algorithm based on Schubfach [4]. From [5]: "In > addition to the core idea of Schubfach, Dragonbox utilizes some > Grisu-like ideas to minimize the number of expensive 128-bit × 64-bit > multiplications, at the cost of having more branches and > divisions-by-constants." > > In the C++ ecosystem, Schubfach has been the fastest known algorithm > before being gently pushed aside by Dragonbox, as can be seen in the > graphs in [3]. > > > > While developing Schubfach back in 2018, I experimented myself with > blending core Schubfach with my own earlier algorithm similar to Grisu. > However, probably due to uncontrollable JIT compilation behavior, I > could not observe any benefit. On the contrary, I measured performance > drops probably because of the added complexity, which is public enemy > nr. 1 for JIT compilers. Therefore, I opted for the simpler current > design that seemed more suitable for (the then 2018 version of) C2. > > > > I hope this can somehow revive this community's interest and confidence > toward Schubfach to definitely supplant the current expensive > (Double|Float)::toString algorithm. > > > Greetings > Raffaello > > ---- > > [1] https://drive.google.com/open?id=1luHhyQF9zKlM8yJ1nebU0OgVYhfC6CBN > [2] > > https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-March/065297.html > [3] https://github.com/abolz/Drachennest > [4] https://github.com/jk-jeon/dragonbox > [5] > https://github.com/jk-jeon/dragonbox/blob/master/other_files/Dragonbox.pdf >
