Struct halo2_proofs::plonk::Selector
source · pub struct Selector(_, _);
Expand description
A selector, representing a fixed boolean value per row of the circuit.
Selectors can be used to conditionally enable (portions of) gates:
use halo2_proofs::poly::Rotation;
let a = meta.advice_column();
let b = meta.advice_column();
let s = meta.selector();
meta.create_gate("foo", |meta| {
let a = meta.query_advice(a, Rotation::prev());
let b = meta.query_advice(b, Rotation::cur());
let s = meta.query_selector(s);
// On rows where the selector is enabled, a is constrained to equal b.
// On rows where the selector is disabled, a and b can take any value.
vec![s * (a - b)]
});
Selectors are disabled on all rows by default, and must be explicitly enabled on each row when required:
use group::ff::Field;
use halo2_proofs::{
circuit::{Chip, Layouter, Value},
plonk::{Advice, Column, Error, Selector},
};
struct Config {
a: Column<Advice>,
b: Column<Advice>,
s: Selector,
}
fn circuit_logic<F: Field, C: Chip<F>>(chip: C, mut layouter: impl Layouter<F>) -> Result<(), Error> {
let config = chip.config();
layouter.assign_region(|| "bar", |mut region| {
region.assign_advice(|| "a", config.a, 0, || Value::known(F::ONE))?;
region.assign_advice(|| "a", config.b, 1, || Value::known(F::ONE))?;
config.s.enable(&mut region, 1)
})?;
Ok(())
}
Implementations§
Trait Implementations§
source§impl From<Selector> for RegionColumn
impl From<Selector> for RegionColumn
source§fn from(selector: Selector) -> RegionColumn
fn from(selector: Selector) -> RegionColumn
Converts to this type from the input type.
source§impl PartialEq<Selector> for Selector
impl PartialEq<Selector> for Selector
impl Copy for Selector
impl Eq for Selector
impl StructuralEq for Selector
impl StructuralPartialEq for Selector
Auto Trait Implementations§
impl RefUnwindSafe for Selector
impl Send for Selector
impl Sync for Selector
impl Unpin for Selector
impl UnwindSafe for Selector
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