halo2_proofs::circuit::layouter

Trait RegionLayouter

Source 
pub trait RegionLayouter<F: Field>: Debug {
    // Required methods
    fn enable_selector<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        selector: &Selector,
        offset: usize,
    ) -> Result<(), Error>;
    fn assign_advice<'v>(
        &'v mut self,
        annotation: &'v (dyn Fn() -> String + 'v),
        column: Column<Advice>,
        offset: usize,
        to: &'v mut (dyn FnMut() -> Result<Assigned<F>, Error> + '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, Option<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() -> Result<Assigned<F>, Error> + '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>;
}
Expand description

Helper trait for implementing a custom Layouter.

This trait is used for implementing region assignments:

ⓘ
impl<'a, F: FieldExt, 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§

Source

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.

Source

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

Assign an advice column value (witness)

Source

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.

Source

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, Option<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, and its value if known.

Source

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

Assign a fixed value

Source

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.

Source

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§

Source§

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

Source§

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

Converts to this type from the input type.

Implementors§