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Docfixes and minor refactors. 

Co-authored-by: Daira Hopwood <daira@jacaranda.org>
This commit is contained in:
therealyingtong 2021-07-15 12:27:12 +08:00
parent b696163e31
commit 425ee6e038
2 changed files with 6 additions and 5 deletions
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8
src/circuit/gadget/ecc/chip/mul_fixed.rs
View File

@ -424,7 +424,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
)?;
}
// offset_acc = \sum_{j = 0}^{NUM_WINDOWS - 2} 2^{FIXED_BASE_WINDOW_SIZE * j+1}
// offset_acc = \sum_{j = 0}^{NUM_WINDOWS - 2} 2^{FIXED_BASE_WINDOW_SIZE*j + 1}
let offset_acc = (0..(NUM_WINDOWS - 1)).fold(pallas::Scalar::zero(), |acc, w| {
acc + (*TWO_SCALAR).pow(&[
constants::FIXED_BASE_WINDOW_SIZE as u64 * w as u64 + 1,
@ -434,7 +434,7 @@ impl<const NUM_WINDOWS: usize> Config<NUM_WINDOWS> {
])
});
// `scalar = [k * 8^84 - offset_acc]`, where `offset_acc = \sum_{j = 0}^{83} 2^{FIXED_BASE_WINDOW_SIZE * j + 1}`.
// `scalar = [k * 8^84 - offset_acc]`, where `offset_acc = \sum_{j = 0}^{83} 2^{FIXED_BASE_WINDOW_SIZE*j + 1}`.
let scalar = scalar.windows_field()[scalar.windows_field().len() - 1]
.map(|k| k * (*H_SCALAR).pow(&[(NUM_WINDOWS - 1) as u64, 0, 0, 0]) - offset_acc);
@ -531,14 +531,14 @@ impl ScalarFixed {
}
// The scalar decomposition is guaranteed to be in three-bit windows,
// so we also cast the least significant byte in their serialisation
// so we also cast the least significant 4 bytes in their serialisation
// into usize for convenient indexing into `u`-values
fn windows_usize(&self) -> Vec<Option<usize>> {
self.windows_field()
.iter()
.map(|window| {
if let Some(window) = window {
let window = window.to_bytes()[0] as usize;
let window = window.get_lower_32() as usize;
assert!(window < constants::H);
Some(window)
} else {

3
src/circuit/gadget/utilities.rs
View File

@ -99,7 +99,8 @@ pub fn transpose_option_array<T: Copy + std::fmt::Debug, const LEN: usize>(
ret
}
/// Subsets a field element to a specified bitrange (little-endian)
/// Takes a specified subsequence of the little-endian bit representation of a field element.
/// The bits are numbered from 0 for the LSB.
pub fn bitrange_subset<F: FieldExt + PrimeFieldBits>(field_elem: F, bitrange: Range<usize>) -> F {
assert!(bitrange.end <= F::NUM_BITS as usize);