binius_core/protocols/gkr_gpa/
packed_field_storage.rs

1// Copyright 2024-2025 Irreducible Inc.
2
3use std::ops::Deref;
4
5use binius_field::PackedField;
6use binius_math::{Error, MultilinearExtension};
7use binius_utils::checked_arithmetics::checked_log_2;
8
9/// Packed field storage that can either reference a full slice of packed field elements or
10/// store a small number of packed field elements (not greater than `P::WIDTH``) in-place.
11#[derive(Debug, Clone, PartialEq, Eq)]
12pub enum PackedFieldStorage<'a, P: PackedField> {
13	SliceRef(&'a [P]),
14	Inline { data: P, size: usize },
15}
16
17impl<'a, P: PackedField> PackedFieldStorage<'a, P> {
18	/// Creates a new packed field storage from an iterator of scalar elements.
19	/// The number of elements in the iterator must not exceed `P::WIDTH`.
20	pub fn new_inline(values: impl Iterator<Item = P::Scalar>) -> Result<Self, Error> {
21		let mut data = P::default();
22		let mut size = 0;
23		for (i, val) in values.enumerate() {
24			data.set_checked(i, val)?;
25			size += 1;
26		}
27		Ok(Self::Inline { data, size })
28	}
29
30	/// Creates a new packed field storage from a slice of packed field elements.
31	pub const fn new_slice(data: &'a [P]) -> Self {
32		Self::SliceRef(data)
33	}
34
35	/// Returns the number of scalar elements in the packed field storage.
36	pub const fn n_scalars(&self) -> usize {
37		match self {
38			PackedFieldStorage::SliceRef(data) => data.len() * P::WIDTH,
39			PackedFieldStorage::Inline { size, .. } => *size,
40		}
41	}
42
43	/// Returns the logarithm of the number of scalar elements in the packed field storage.
44	/// Panics if the number of scalar elements is not a power of 2.
45	pub fn log_n_scalars(&self) -> Option<usize> {
46		self.n_scalars()
47			.is_power_of_two()
48			.then(|| checked_log_2(self.n_scalars()))
49	}
50}
51
52impl<'a, P: PackedField> From<&'a [P]> for PackedFieldStorage<'a, P> {
53	fn from(data: &'a [P]) -> Self {
54		PackedFieldStorage::new_slice(data)
55	}
56}
57
58impl<P: PackedField> Deref for PackedFieldStorage<'_, P> {
59	type Target = [P];
60
61	fn deref(&self) -> &Self::Target {
62		match self {
63			PackedFieldStorage::SliceRef(data) => data,
64			PackedFieldStorage::Inline { data, .. } => std::slice::from_ref(data),
65		}
66	}
67}
68
69impl<'a, P: PackedField> TryFrom<PackedFieldStorage<'a, P>>
70	for MultilinearExtension<P, PackedFieldStorage<'a, P>>
71{
72	type Error = Error;
73
74	fn try_from(storage: PackedFieldStorage<'a, P>) -> Result<Self, Error> {
75		Self::new(
76			storage
77				.log_n_scalars()
78				.ok_or(binius_math::Error::PowerOfTwoLengthRequired)?,
79			storage,
80		)
81	}
82}
binius_core/protocols/gkr_gpa/packed_field_storage.rs

binius_core/protocols/gkr_gpa/
packed_field_storage.rs
