Herbie 1.0 Release Notes

After two years of work, the Herbie developers are excited to announce Herbie 1.0! This is the first release of Herbie, marking its transition from research software to a tool for scientists and engineers to improve the accuracy of their floating point software.

Herbie automatically improves the accuracy of floating point expressions. This avoids the bugs, errors, and surprises that so often occur when working with floating point. Since our PLDI'15 paper, we've been hard at work making Herbie more versatile and easier to use.

Usability improvements

• A switch to the standard FPCore input format. This makes it easy to use Herbie together with other floating point tools, like Herbgrind.
• A web demo, which makes it easy to try out Herbie and also gives us a sense of what problems people are trying to solve using Herbie.
• Easier installation. We've removed dependencies on several external libraries, upgraded to the latest versions of Racket, and eliminated a confusing linking step.
• OS X support. We've tracked down several bugs that prevented Herbie from working on OS X.
• Support for more functions. Every function available in math.h is supported, and some additional functions from GNU libc are as well.
• Docker support for Herbie. You can now use the popular container tool to make installation even easier.
• More informative report pages, visible in the web demo, which makes them more useful both for users and for debugging. In particular, the new graph gives a quick overview of how Herbie did on a collection of inputs.
• Make it possible to toggle rulesets in Herbie.
• A new entry point into Herbie, cleaning up a haphazard collection of different scripts.
• New website!

Improvement to core algorithm

• Herbie is now faster! A new measurement infrastructure helped us track down some time sinks.
• Bounds on variables. You can now specifiy bounds within which to sample variables.
• Branch on expressions. Herbie can now sometimes infer conditionals that use expressions, not variables, to determine which expression to use.
• Support expansions around ±∞ in Taylor expansions. The framework behind this should eventually make it possible to support Puiseux series as well.
• Simplify expressions such as (exp 1) or (cos PI), by supporting symbolic constants in the simplification algorithm.
• Faster Taylor series routine. Several large tweaks have helped make Taylor series orders of magnitude faster, which has sped up Herbie.

Code Cleanup

• Use a proper parser for input files. We used to use a bizarre system of evaling input files and poking around global storage for the results.
• Many crashes fixed. Herbie is stabler than ever!
• A new debugging and logging system, which makes Herbie debugging from the REPL significantly easier
• A new measurement system that lets us see where Herbie spend its time. This has helped speed up Herbie.
• A new implementation of the Herbie main loop, which is much easier to work with in the debugger.
• Unit tests and more integration with the Racket toolchain.
• A fuzzer for Herbie, which has allowed us to track down many bugs.

Try it out!

We're excited to continue to improve Herbie and make it more useful to scientists, engineers, and programmers around the world. We've got a lot of features we're excited to work on in the coming months. Please report bugs, join the mailing list, or contribute.

If you find Herbie useful, let us know!