From 8f929888afbacdab1a7469720b05cb82cf588580 Mon Sep 17 00:00:00 2001 From: str4d Date: Fri, 11 Dec 2020 18:34:59 +0000 Subject: [PATCH] book: Describe a lookup table as representing a relation Co-authored-by: Daira Hopwood --- book/src/user/lookup-tables.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/book/src/user/lookup-tables.md b/book/src/user/lookup-tables.md index 25e60e9..2709a94 100644 --- a/book/src/user/lookup-tables.md +++ b/book/src/user/lookup-tables.md @@ -4,4 +4,8 @@ In normal programs, you can trade memory for CPU to improve performance, by pre- and storing lookup tables for some part of the computation. We can do the same thing in halo2 circuits! +A lookup table can be thought of as enforcing a *relation* between variables, where the relation is expressed as a table. +Assuming we have only one lookup argument in our constraint system, the total size of tables is constrained by the size of the circuit: +each table entry costs one row, and it also costs one row to do each lookup. + TODO