h3lio5 / halo2-sorting-algorithms

Implementation of sorting algorithms in halo2.

halo2-sorting-algorithms

Implementation of sorting algorithms in halo2.

High-level design

Bubblesort

Goal: Implement the bubblesort sorting algorithm in halo2 proving each step of the algorithm.
Notes:

• The Plonkish table has 1 selector column, ARR_SIZE number of advice columns for storing array elements, 2 advice columns for the swapped elements per (swap) step, 1 range check table used by the is_less_than gadget, 1 instance column to expose the input and output array.
• Layout of the Plonkish table is as follows:

 __________________________________________________________________________________________________________
| q_swap_index | arr_0 | arr_1 | ... | arr_(ARR_SIZE-1) | range_check table | value_l | value_r | instance |
|-------------------------------------------------------------------------------------|--------------------|
|              |       |       |     |                  |                   |         |         |          | 
|              |       |       |     |                  |                   |         |         |          |
.              .       .       .     .                  .                   .         .         .          .
.              .       .       .     .                  .                   .         .         .          .
.              .       .       .     .                  .                   .         .         .          .
|______________|_______|_______|_____|__________________|___________________|_________|_________|__________|

• Each row of the advice columns stores the resulting array after each swap step of bubblesort, the swapped elements are copied to the value_l, value_r advice columns, which the is_less_than gadget uses to perform the check.