ark_r1cs_std::select

Trait ThreeBitCondNegLookupGadget

Source 
pub trait ThreeBitCondNegLookupGadget<ConstraintF: Field>: Sized {
    type TableConstant;

    // Required method
    fn three_bit_cond_neg_lookup(
        bits: &[Boolean<ConstraintF>],
        b0b1: &Boolean<ConstraintF>,
        constants: &[Self::TableConstant],
    ) -> Result<Self, SynthesisError>;
}
Expand description

Uses three bits to perform a lookup into a table, where the last bit conditionally negates the looked-up value.

Required Associated Types§

Source

type TableConstant

The type of values being looked up.

Required Methods§

Source

fn three_bit_cond_neg_lookup( bits: &[Boolean<ConstraintF>], b0b1: &Boolean<ConstraintF>, constants: &[Self::TableConstant], ) -> Result<Self, SynthesisError>

Interprets the slice bits as a two-bit integer b = bits[0] + (bits[1] << 1), and then outputs constants[b] * c, where c = if bits[2] { -1 } else { 1 };.

That is, bits[2] conditionally negates the looked-up value.

For example, if bits == [1, 0, 1], and constants == [0, 1, 2, 3], this method should output a variable corresponding to -1.

§Panics

This method panics if bits.len() != 3 or constants.len() != 4.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§