Trait kimchi_msm::circuit_design::capabilities::HybridCopyCap

pub trait HybridCopyCap<F: PrimeField, CIx: ColumnIndexer>where
    Self: ColAccessCap<F, CIx>,{
    // Required method
    fn hcopy(&mut self, x: &Self::Variable, ix: CIx) -> Self::Variable;
}

Capability for computing arithmetic functions and enforcing constraints simultaneously.

The “hybrid” in the name of the trait (and other traits here) means “maybe”.

That is, it allows computations which /might be/ no-ops (even partially) in the constraint builder case. For example, “hcopy”, despite its name, does not do any “write”, so hcopy !=> write_column.

Required Methods

fn hcopy(&mut self, x: &Self::Variable, ix: CIx) -> Self::Variable

Given variable x and position ix, it (hybrid) writes x into ix, and returns the value.

Implementors

impl<'a, F: PrimeField, CIx1: ColumnIndexer, CIx2: ColumnIndexer, Env1: HybridCopyCap<F, CIx1>, L: MPrism<Source = CIx1, Target = CIx2>> HybridCopyCap<F, CIx2> for SubEnvColumn<'a, F, CIx1, Env1, L>

impl<'a, F: PrimeField, CIx1: ColumnIndexer, Env1: HybridCopyCap<F, CIx1>, L> HybridCopyCap<F, CIx1> for SubEnvLookup<'a, F, CIx1, Env1, L>

impl<F: PrimeField, CIx: ColumnIndexer, LT: LookupTableID> HybridCopyCap<F, CIx> for ConstraintBuilderEnv<F, LT>

impl<F: PrimeField, CIx: ColumnIndexer, const N_WIT: usize, const N_REL: usize, const N_DSEL: usize, const N_FSEL: usize, LT: LookupTableID> HybridCopyCap<F, CIx> for WitnessBuilderEnv<F, CIx, N_WIT, N_REL, N_DSEL, N_FSEL, LT>

If Env implements real write (“for sure” writes), you can implement hybrid copy (that is only required to “maybe” copy). The other way around violates the semantics.

Sadly, rust does not allow “cover” instances to define this impl for every T: ColWriteCap.