Module kimchi::circuits::berkeley_columns

This module defines the particular form of the expressions used in the Mina Berkeley hardfork. You can find more information in this blog article. This module is also a good starting point if you want to implement your own variant of Kimchi using the expression framework.

The module uses the generic expression framework defined in the crate::circuits::expr module. The expressions define the polynomials that can be used to describe the constraints. It starts by defining the different challenges used by the PLONK IOP in BerkeleyChallengeTerm and BerkeleyChallenges. It then defines the Column type which represents the different variables the polynomials are defined over.

Two “environments” are after that defined: one for the lookup argument LookupEnvironment, and one for the main argument Environment, which contains the former. The trait ColumnEnvironment is then defined to provide the necessary primitives used to evaluate the quotient polynomial.

Structs

• BerkeleyChallenges
• Environment
  The collection of polynomials (all in evaluation form) and constants required to evaluate an expression as a polynomial.
• LookupEnvironment
  The polynomials specific to the lookup argument.

Enums

• BerkeleyChallengeTerm
  The challenge terms used in Berkeley.
• Column
  A type representing the variables involved in the constraints of the Berkeley hardfork.

Functions

• coeff
• constant
  Convenience function to create a constant as Expr.
• index
  Handy function to quickly create an expression for a gate.
• witness
  Helper function to quickly create an expression for a witness.
• witness_curr
  Same as witness but for the current row.
• witness_next
  Same as witness but for the next row.

Type Definitions

• E
  An alias for the intended usage of the expression type in constructing constraints.