Struct PeriodicColumns 

pub struct PeriodicColumns<'a, F> { /* private fields */ }

Periodic columns screened against the rows they have to cover.

A column of length p holds the evaluations of one polynomial over a subgroup of order p.

• Such a subgroup exists only when p is a power of two.
• It tiles the rows only when p divides the height.

    height 8,  length 2   [0,1][0,1][0,1][0,1]       tiles
    height 8,  length 16  [0,1,...,7|8,...,15]       truncated
    height 12, length 8   [0,...,7][0,1,2,3|4,...]   partial repeat

Row lookups wrap with row mod p, so an ill-shaped column still yields a value on every row. Reading rows alone never reveals the mistake.

Evaluation is where it breaks. Every path divides the height by the length and takes a base-two logarithm of the quotient. Neither step means anything for a shape the rule rejects.

Holding this view is the evidence that the rule was applied.

Implementations

impl<'a, F> PeriodicColumns<'a, F>

pub fn new( columns: &'a [Vec<F>], height: usize, ) -> Result<Self, PeriodicColumnShapeError>

Screen the declared columns against the rows they have to cover.

Errors

• A length that is not a power of two, zero included.
• A length that does not divide the height.

pub const fn as_slice(&self) -> &'a [Vec<F>]

The screened columns, in declaration order.

pub const fn height(&self) -> usize

Rows the columns were screened against.

pub const fn len(&self) -> usize

How many columns are declared.

pub const fn is_empty(&self) -> bool

True when the declaration is empty.

pub fn max_period(&self) -> Option<usize>

Longest declared period, absent when the declaration is empty.

Every period divides the height, so the longest one divides it too. Padding every column up to it yields one rectangular table over a single subgroup.

Trait Implementations

impl<F> Clone for PeriodicColumns<'_, F>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<F> Copy for PeriodicColumns<'_, F>

impl<'a, F: Debug> Debug for PeriodicColumns<'a, F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.