Herbie 1.1 Release Notes

After six months of work, the Herbie developers are excited to announce Herbie 1.1! This release focuses on making Herbie easier to use, including a web interface, clear syntax errors, and detailed reports. This release also expands support for trigonometric and hyperbolic functions, and speeds up preconditions.

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.

Breaking Changes and Deprecations

• In line with FPCore 1.0, we have removed support for the cotan function, renamed = to ==, and added the != function.
• In line with the new syntax for calling Herbie from the command line, the old syntax is deprecated and will be removed in the next version.
• In line with the faster preconditions, we have deprecated the :herbie-samplers property and will remove it in the next release.
• We have changed the syntax for specifying search options for Herbie. Instead of using -o to toggle options, use -o to disable options and +o to enable them.

Usability improvements

• HTML reports. Herbie can now generate reports that show graphs, describe how Herbie achieved its result, and more.
• Web shell. The old web demo has been cleaned up and made available to users, providing a graphical interface to Herbie.
• Batch mode. It's now simpler to run Herbie on an FPCore file and save the results in an output file. The command-line shell is also more user-friendly.
• Easier installation using the Racket package manager.
• Simpler, clearer syntax errors. Instead of stack traces, syntax errors now come with file, line, and column information.

Improvement to core algorithm

• Faster preconditions. A precondition like (< 10 x 12) now causes Herbie to only sample points in the relevant range, significantly speeding up Herbie and obviating many "cannot sample enough valid points" errors.
• Better support for trigonometric and hyperbolic functions. We've taught Herbie about many trigonometric identities, which it can now use to improve expressions.
• Better series expansion. We've taught Herbie to take series expansions of many more functions.
• Zero-argument expressions are now supported.

Code Cleanup

• We have a new, right-facing logo!
• We now have a complete syntax checker for inputs, giving the Herbie core confidence that it's dealing with valid expressions.
• The infrastructure for generating reports has been cleaned up.
• The web demo has been rearchitected. It no longer needs to output files, no longer uses continuations, and is now much more configurable.
• The new command-line syntax unifies the mess of invokable scripts in Herbie. We will continue the unification in future releases.
• More unit tests continue to be written, and including a test that ensures that all our rules are valid.

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!