pub trait FftParameters: 'static + Send + Sync + Sized {
    type BigInteger: BigInteger;

    const TWO_ADICITY: u32;
    const TWO_ADIC_ROOT_OF_UNITY: Self::BigInteger;
    const POWERS_OF_ROOTS_OF_UNITY: &'static [Self::BigInteger];
    const SMALL_SUBGROUP_BASE: Option<u32> = None;
    const SMALL_SUBGROUP_BASE_ADICITY: Option<u32> = None;
    const LARGE_SUBGROUP_ROOT_OF_UNITY: Option<Self::BigInteger> = None;
}
Expand description

A trait that defines parameters for a field that can be used for FFTs.

Required Associated Types§

Required Associated Constants§

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const TWO_ADICITY: u32

Let N be the size of the multiplicative group defined by the field. Then TWO_ADICITY is the two-adicity of N, i.e. the integer s such that N = 2^s * t for some odd integer t. 2^s * t = MODULUS - 1 with t odd. This is the two-adicity of the prime.

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const TWO_ADIC_ROOT_OF_UNITY: Self::BigInteger

2^s root of unity, defined as GENERATOR^t.

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const POWERS_OF_ROOTS_OF_UNITY: &'static [Self::BigInteger]

TWO_ADIC_ROOT_OF_UNITY^2^i for i := 0..TWO_ADICITY-1

Provided Associated Constants§

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const SMALL_SUBGROUP_BASE: Option<u32> = None

An integer b such that there exists a multiplicative subgroup of size b^k for some integer k.

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const SMALL_SUBGROUP_BASE_ADICITY: Option<u32> = None

The integer k such that there exists a multiplicative subgroup of size Self::SMALL_SUBGROUP_BASE^k.

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const LARGE_SUBGROUP_ROOT_OF_UNITY: Option<Self::BigInteger> = None

GENERATOR^((MODULUS-1) / (2^s * SMALL_SUBGROUP_BASE^SMALL_SUBGROUP_BASE_ADICITY)) Used for mixed-radix FFT.

Object Safety§

This trait is not object safe.

Implementors§