Trait halo2_frontend::circuit::layouter::RegionLayouter

pub trait RegionLayouter<F: Field>: Debug + SyncDeps {
    // Required methods
    fn enable_selector<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        selector: &Selector,
        offset: usize
    ) -> Result<(), Error>;
    fn name_column<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        column: Column<Any>
    );
    fn assign_advice<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        column: Column<Advice>,
        offset: usize,
        to: &'v mut (dyn FnMut() -> Value<Assigned<F>> + 'v)
    ) -> Result<Cell, Error>;
    fn assign_advice_from_constant<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        column: Column<Advice>,
        offset: usize,
        constant: Assigned<F>
    ) -> Result<Cell, Error>;
    fn assign_advice_from_instance<'v>(
        &mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        instance: Column<Instance>,
        row: usize,
        advice: Column<Advice>,
        offset: usize
    ) -> Result<(Cell, Value<F>), Error>;
    fn instance_value(
        &mut self,
        instance: Column<Instance>,
        row: usize
    ) -> Result<Value<F>, Error>;
    fn assign_fixed<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        column: Column<Fixed>,
        offset: usize,
        to: &'v mut (dyn FnMut() -> Value<Assigned<F>> + 'v)
    ) -> Result<Cell, Error>;
    fn constrain_constant(
        &mut self,
        cell: Cell,
        constant: Assigned<F>
    ) -> Result<(), Error>;
    fn constrain_equal(&mut self, left: Cell, right: Cell) -> Result<(), Error>;
}

Helper trait for implementing a custom Layouter.

This trait is used for implementing region assignments:

impl<'a, F: Field, C: Chip<F>, CS: Assignment<F> + 'a> Layouter<C> for MyLayouter<'a, C, CS> {
    fn assign_region(
        &mut self,
        assignment: impl FnOnce(Region<'_, F, C>) -> Result<(), Error>,
    ) -> Result<(), Error> {
        let region_index = self.regions.len();
        self.regions.push(self.current_gate);

        let mut region = MyRegion::new(self, region_index);
        {
            let region: &mut dyn RegionLayouter<F> = &mut region;
            assignment(region.into())?;
        }
        self.current_gate += region.row_count;

        Ok(())
    }
}

TODO: It would be great if we could constrain the columns in these types to be “logical” columns that are guaranteed to correspond to the chip (and have come from Chip::Config).

Required Methods

fn enable_selector<'v>( &'v mut self, annotation: &'v (dyn Fn() -> String + 'v), selector: &Selector, offset: usize ) -> Result<(), Error>

Enables a selector at the given offset.

fn name_column<'v>( &'v mut self, annotation: &'v (dyn Fn() -> String + 'v), column: Column<Any> )

Allows the circuit implementor to name/annotate a Column within a Region context.

This is useful in order to improve the amount of information that prover.verify() and prover.assert_satisfied() can provide.

fn assign_advice<'v>( &'v mut self, annotation: &'v (dyn Fn() -> String + 'v), column: Column<Advice>, offset: usize, to: &'v mut (dyn FnMut() -> Value<Assigned<F>> + 'v) ) -> Result<Cell, Error>

Assign an advice column value (witness)

fn assign_advice_from_constant<'v>( &'v mut self, annotation: &'v (dyn Fn() -> String + 'v), column: Column<Advice>, offset: usize, constant: Assigned<F> ) -> Result<Cell, Error>

Assigns a constant value to the column advice at offset within this region.

The constant value will be assigned to a cell within one of the fixed columns configured via ConstraintSystem::enable_constant.

Returns the advice cell that has been equality-constrained to the constant.

fn assign_advice_from_instance<'v>( &mut self, annotation: &'v (dyn Fn() -> String + 'v), instance: Column<Instance>, row: usize, advice: Column<Advice>, offset: usize ) -> Result<(Cell, Value<F>), Error>

Assign the value of the instance column’s cell at absolute location row to the column advice at offset within this region.

Returns the advice cell that has been equality-constrained to the instance cell, and its value if known.

fn instance_value( &mut self, instance: Column<Instance>, row: usize ) -> Result<Value<F>, Error>

Returns the value of the instance column’s cell at absolute location row.

fn assign_fixed<'v>( &'v mut self, annotation: &'v (dyn Fn() -> String + 'v), column: Column<Fixed>, offset: usize, to: &'v mut (dyn FnMut() -> Value<Assigned<F>> + 'v) ) -> Result<Cell, Error>

Assigns a fixed value

fn constrain_constant( &mut self, cell: Cell, constant: Assigned<F> ) -> Result<(), Error>

Constrains a cell to have a constant value.

Returns an error if the cell is in a column where equality has not been enabled.

fn constrain_equal(&mut self, left: Cell, right: Cell) -> Result<(), Error>

Constraint two cells to have the same value.

Returns an error if either of the cells is not within the given permutation.

Trait Implementations

impl<'r, F: Field> From<&'r mut dyn RegionLayouter<F>> for Region<'r, F>

fn from(region: &'r mut dyn RegionLayouter<F>) -> Self

Converts to this type from the input type.

Implementors

impl<F: Field> RegionLayouter<F> for RegionShape