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A comment on Herbie: Automatically rewrites expressions to minimize floating point error.

Re:Herbie: Automatically rewrites expressions to minimize fl... by adamjs on Sunday January 24, 2016 @09:01PM (#10965164)
The OP copied only half my tweet, full title should be "...to minimize floating-point precision errors". This tool is specifically for improving the numerical accuracy of equations when translated into floating-point code-- "minimizing errors" makes no sense without the qualifiers.

I do a lot of procedural graphics on the GPU and am constantly plagued by precision issues (you cannot copy equations verbatim into code, you must observe overflow/underflow and other numerical issues). Herbie is pretty magical in that it can _automatically_ translate math expressions into a form that's friendlier for computers.

Also the reason why the GitHub site source was linked is because the website [1] crashed under traffic earlier today (full site contains an interactive solver and examples).

[1] http://herbie.uwplse.org/

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Re:Herbie: Automatically rewrites expressions to minimize fl... by jacobolus on Sunday January 24, 2016 @09:22PM (#10965236)
Do you have an example of a graphics algorithm that you were helped with by this tool / a description of how that went?
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Re:Herbie: Automatically rewrites expressions to minimize fl... by adamjs on Sunday January 24, 2016 @09:41PM (#10965276)
There's actually a great write-up on how Herbie was used in the real-world to fix and improve math.js: https://pavpanchekha.com/blog/casio-mathjs.html

I've personally used it for improving some distance-field approximation code on the GPU (made it easier to translate the math into numerically-stable code).

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Re:Herbie: Automatically rewrites expressions to minimize fl... by pavpanchekha on Monday January 25, 2016 @11:23AM (#10968016)
Adam, I'm one of the authors of Herbie. I'd love to hear about the distance-field approximation code you improved using Herbie. Is there any chance you can email me some details? You can use my personal email (on my profile) or the [email protected] mailing list.
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Re:Herbie: Automatically rewrites expressions to minimize fl... by dang on Monday January 25, 2016 @12:25AM (#10965752)
Ok, we changed the title from "Herbie: A tool to automatically rewrite arithmetic expressions to minimize error" to be closer to what you've said here. If anyone can suggest a better (more accurate and neutral) title, we can change it again.
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Re:Herbie: Automatically rewrites expressions to minimize fl... by _0ffh on Monday January 25, 2016 @07:46AM (#10966852)
Wouldn't it need to know the probable value ranges of the input variables?
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Re:Herbie: Automatically rewrites expressions to minimize fl... by Natsu on Monday January 25, 2016 @12:54AM (#10965819)
I think it would be interesting if something like this could be chosen as a compiler optimization.
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Re:Herbie: Automatically rewrites expressions to minimize fl... by davmre on Monday January 25, 2016 @01:00AM (#10965834)
It can if you use Haskell: https://github.com/mikeizbicki/HerbiePlugin
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