plonky2/starky/src/util.rs

//! Utility module providing some helper functions.

#[cfg(not(feature = "std"))]
use alloc::vec::Vec;

use itertools::Itertools;
use plonky2::field::polynomial::PolynomialValues;
use plonky2::field::types::Field;
use plonky2::util::transpose;

/// A helper function to transpose a row-wise trace and put it in the format that `prove` expects.
pub fn trace_rows_to_poly_values<F: Field, const COLUMNS: usize>(
    trace_rows: Vec<[F; COLUMNS]>,
) -> Vec<PolynomialValues<F>> {
    let trace_row_vecs = trace_rows.into_iter().map(|row| row.to_vec()).collect_vec();
    let trace_col_vecs: Vec<Vec<F>> = transpose(&trace_row_vecs);
    trace_col_vecs
        .into_iter()
        .map(|column| PolynomialValues::new(column))
        .collect()
}