Axiom Equality Constraints

[jp4g]

Given requirements for interoperating between axiom gate chips and standard halo2 chips (given with example of keccak rather than StandardPlonk, but same process):

• Do halo2-lib computations, make calls to KeccakChip to have keccak do witness generation, return all witness cells to be assigned in keccak part of the arithmetization
• Actually assign keccak part in vanilla halo2, returning AssignedCells: https://github.com/axiom-crypto/axiom-eth/blob/6d2a4acf559a8716b867a715f3acfab745fbad3f/src/keccak/mod.rs#LL751C35-L751C35
• Need to do some tricks to convert AssignedCells to AssignedValues (basically just some way to make copy constraints between halo2-lib and keccak cells): https://github.com/axiom-crypto/axiom-eth/blob/6d2a4acf559a8716b867a715f3acfab745fbad3f/src/keccak/mod.rs#L423
• Now assign halo2-lib AssignedValues into vanilla halo2, where it already has access to the assigned keccak cells, so it can do copy constraints appropriately: https://github.com/axiom-crypto/axiom-eth/blob/6d2a4acf559a8716b867a715f3acfab745fbad3f/src/keccak/mod.rs#LL778C18-L778C18

Likely requires a custom thread builder!

[ameya-deshmukh]

Hey @jp4g ! Saw your comment on this in the halo2-lib discussion TG as well. Would you require help with this? Would be delighted to contribute

[jp4g]

Hey @jp4g ! Saw your comment on this in the halo2-lib discussion TG as well. Would you require help with this? Would be delighted to contribute

DM'd on telegram, ty! If you'd prefer to do things publicly in this issue though we can work from this issue