Herbie can be used from the command-line or from the browser. This page covers using Herbie from the command line.
The Herbie shell lets you interact with Herbie: you type in input expressions and Herbie prints their more accurate versions. Run the Herbie shell with this command:
herbie shell Herbie 2.0 with seed 2098242187 Find help on https://herbie.uwplse.org/, exit with Ctrl-D herbie>
Herbie prints a seed, which you can use to reproduce a Herbie run, and links you to documentation. Then, it waits for inputs, which you can type directly into your terminal in FPCore format:
herbie> (FPCore (x) (- (+ 1 x) x)) (FPCore (x) ... 1)
Herbie suggests that
1 is more accurate than the
(- (+ 1 x) x). The
the ... elides
additional information provided
The Herbie shell only shows Herbie's most accurate variant.
Alternatively, you can run Herbie on a file with multiple expressions in it, writing Herbie's versions of each to a file. This mode is intended for use by scripts.
herbie improve bench/tutorial.fpcore out.fpcore Starting Herbie on 3 problems (seed: 1551571787)... 1/3 [ 0.882s] 30→ 0 Cancel like terms Warning: 24.7% of points produce a very large (infinite) output. You may want to add a precondition. See <https://herbie.uwplse.org/doc/2.0/faq.html#inf-points> for more. 2/3 [ 1.721s] 29→ 0 Expanding a square 3/3 [ 2.426s] 0→ 0 Commute and associate
The output file
out.fpcore contains more accurate
versions of each program:
;; seed: 1551571787 (FPCore (x) ... 1) (FPCore (x) ... (* x (- x -2))) (FPCore (x y z) ... 0)
Note that output file is in the same order as the input file. For more control over Herbie, see the documentation of Herbie's command-line options.