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ggsw.rs
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ggsw.rs
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use super::super::math::decomposition::TensorSignedDecompositionLendingIter;
use super::super::math::fft::{FftView, FourierPolynomialList};
use super::super::math::polynomial::{FourierPolynomialMutView, FourierPolynomialView};
use crate::core_crypto::commons::math::decomposition::{DecompositionLevel, SignedDecomposer};
use crate::core_crypto::commons::math::torus::UnsignedTorus;
use crate::core_crypto::commons::parameters::{
DecompositionBaseLog, DecompositionLevelCount, GlweSize, PolynomialSize,
};
use crate::core_crypto::commons::traits::{
Container, ContiguousEntityContainer, ContiguousEntityContainerMut, IntoContainerOwned, Split,
};
use crate::core_crypto::commons::utils::izip;
use crate::core_crypto::entities::*;
use aligned_vec::{avec, ABox, CACHELINE_ALIGN};
use concrete_fft::c64;
use dyn_stack::{PodStack, ReborrowMut, SizeOverflow, StackReq};
#[cfg(target_arch = "x86")]
use core::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64::*;
/// A GGSW ciphertext in the Fourier domain.
#[derive(Clone, Copy, Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
#[serde(bound(deserialize = "C: IntoContainerOwned"))]
pub struct FourierGgswCiphertext<C: Container<Element = c64>> {
fourier: FourierPolynomialList<C>,
glwe_size: GlweSize,
decomposition_base_log: DecompositionBaseLog,
decomposition_level_count: DecompositionLevelCount,
}
/// A matrix containing a single level of gadget decomposition, in the Fourier domain.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct FourierGgswLevelMatrix<C: Container<Element = c64>> {
data: C,
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
row_count: usize,
decomposition_level: DecompositionLevel,
}
/// A row of a GGSW level matrix, in the Fourier domain.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct FourierGgswLevelRow<C: Container<Element = c64>> {
data: C,
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
decomposition_level: DecompositionLevel,
}
pub type FourierGgswCiphertextView<'a> = FourierGgswCiphertext<&'a [c64]>;
pub type FourierGgswCiphertextMutView<'a> = FourierGgswCiphertext<&'a mut [c64]>;
pub type FourierGgswLevelMatrixView<'a> = FourierGgswLevelMatrix<&'a [c64]>;
pub type FourierGgswLevelMatrixMutView<'a> = FourierGgswLevelMatrix<&'a mut [c64]>;
pub type FourierGgswLevelRowView<'a> = FourierGgswLevelRow<&'a [c64]>;
pub type FourierGgswLevelRowMutView<'a> = FourierGgswLevelRow<&'a mut [c64]>;
impl<C: Container<Element = c64>> FourierGgswCiphertext<C> {
pub fn from_container(
data: C,
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
decomposition_base_log: DecompositionBaseLog,
decomposition_level_count: DecompositionLevelCount,
) -> Self {
assert_eq!(
data.container_len(),
polynomial_size.to_fourier_polynomial_size().0
* glwe_size.0
* glwe_size.0
* decomposition_level_count.0
);
Self {
fourier: FourierPolynomialList {
data,
polynomial_size,
},
glwe_size,
decomposition_base_log,
decomposition_level_count,
}
}
pub fn polynomial_size(&self) -> PolynomialSize {
self.fourier.polynomial_size
}
pub fn glwe_size(&self) -> GlweSize {
self.glwe_size
}
pub fn decomposition_base_log(&self) -> DecompositionBaseLog {
self.decomposition_base_log
}
pub fn decomposition_level_count(&self) -> DecompositionLevelCount {
self.decomposition_level_count
}
pub fn data(self) -> C {
self.fourier.data
}
pub fn as_view(&self) -> FourierGgswCiphertextView<'_>
where
C: AsRef<[c64]>,
{
FourierGgswCiphertextView {
fourier: FourierPolynomialList {
data: self.fourier.data.as_ref(),
polynomial_size: self.fourier.polynomial_size,
},
glwe_size: self.glwe_size,
decomposition_base_log: self.decomposition_base_log,
decomposition_level_count: self.decomposition_level_count,
}
}
pub fn as_mut_view(&mut self) -> FourierGgswCiphertextMutView<'_>
where
C: AsMut<[c64]>,
{
FourierGgswCiphertextMutView {
fourier: FourierPolynomialList {
data: self.fourier.data.as_mut(),
polynomial_size: self.fourier.polynomial_size,
},
glwe_size: self.glwe_size,
decomposition_base_log: self.decomposition_base_log,
decomposition_level_count: self.decomposition_level_count,
}
}
}
impl<C: Container<Element = c64>> FourierGgswLevelMatrix<C> {
pub fn new(
data: C,
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
row_count: usize,
decomposition_level: DecompositionLevel,
) -> Self {
assert_eq!(
data.container_len(),
polynomial_size.to_fourier_polynomial_size().0 * glwe_size.0 * row_count
);
Self {
data,
polynomial_size,
glwe_size,
row_count,
decomposition_level,
}
}
/// Return an iterator over the rows of the level matrices.
pub fn into_rows(self) -> impl DoubleEndedIterator<Item = FourierGgswLevelRow<C>>
where
C: Split,
{
self.data
.split_into(self.row_count)
.map(move |slice| FourierGgswLevelRow {
data: slice,
polynomial_size: self.polynomial_size,
glwe_size: self.glwe_size,
decomposition_level: self.decomposition_level,
})
}
pub fn polynomial_size(&self) -> PolynomialSize {
self.polynomial_size
}
pub fn glwe_size(&self) -> GlweSize {
self.glwe_size
}
pub fn row_count(&self) -> usize {
self.row_count
}
pub fn decomposition_level(&self) -> DecompositionLevel {
self.decomposition_level
}
pub fn data(self) -> C {
self.data
}
}
impl<C: Container<Element = c64>> FourierGgswLevelRow<C> {
pub fn new(
data: C,
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
decomposition_level: DecompositionLevel,
) -> Self {
assert_eq!(
data.container_len(),
polynomial_size.to_fourier_polynomial_size().0 * glwe_size.0
);
Self {
data,
polynomial_size,
glwe_size,
decomposition_level,
}
}
pub fn polynomial_size(&self) -> PolynomialSize {
self.polynomial_size
}
pub fn glwe_size(&self) -> GlweSize {
self.glwe_size
}
pub fn decomposition_level(&self) -> DecompositionLevel {
self.decomposition_level
}
pub fn data(self) -> C {
self.data
}
}
impl<'a> FourierGgswCiphertextView<'a> {
/// Return an iterator over the level matrices.
pub fn into_levels(self) -> impl DoubleEndedIterator<Item = FourierGgswLevelMatrixView<'a>> {
self.fourier
.data
.split_into(self.decomposition_level_count.0)
.enumerate()
.map(move |(i, slice)| {
FourierGgswLevelMatrixView::new(
slice,
self.glwe_size,
self.fourier.polynomial_size,
self.glwe_size.0,
DecompositionLevel(i + 1),
)
})
}
}
/// Return the required memory for [`FourierGgswCiphertextMutView::fill_with_forward_fourier`].
pub fn fill_with_forward_fourier_scratch(fft: FftView<'_>) -> Result<StackReq, SizeOverflow> {
fft.forward_scratch()
}
impl<'a> FourierGgswCiphertextMutView<'a> {
/// Fill a GGSW ciphertext with the Fourier transform of a GGSW ciphertext in the standard
/// domain.
pub fn fill_with_forward_fourier<Scalar: UnsignedTorus>(
self,
coef_ggsw: GgswCiphertextView<'_, Scalar>,
fft: FftView<'_>,
mut stack: PodStack<'_>,
) {
debug_assert_eq!(coef_ggsw.polynomial_size(), self.polynomial_size());
let fourier_poly_size = coef_ggsw.polynomial_size().to_fourier_polynomial_size().0;
for (fourier_poly, coef_poly) in izip!(
self.data().into_chunks(fourier_poly_size),
coef_ggsw.as_polynomial_list().iter()
) {
fft.forward_as_torus(
FourierPolynomialMutView { data: fourier_poly },
coef_poly,
stack.rb_mut(),
);
}
}
}
#[allow(unused)]
type FourierGgswCiphertextOwned = FourierGgswCiphertext<ABox<[c64]>>;
impl FourierGgswCiphertext<ABox<[c64]>> {
pub fn new(
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
decomposition_base_log: DecompositionBaseLog,
decomposition_level_count: DecompositionLevelCount,
) -> FourierGgswCiphertext<ABox<[c64]>> {
let boxed = avec![
c64::default();
polynomial_size.to_fourier_polynomial_size().0
* glwe_size.0
* glwe_size.0
* decomposition_level_count.0
]
.into_boxed_slice();
FourierGgswCiphertext::from_container(
boxed,
glwe_size,
polynomial_size,
decomposition_base_log,
decomposition_level_count,
)
}
}
/// Return the required memory for [`add_external_product_assign`].
pub fn add_external_product_assign_scratch<Scalar>(
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
fft: FftView<'_>,
) -> Result<StackReq, SizeOverflow> {
let align = CACHELINE_ALIGN;
let standard_scratch =
StackReq::try_new_aligned::<Scalar>(glwe_size.0 * polynomial_size.0, align)?;
let fourier_polynomial_size = polynomial_size.to_fourier_polynomial_size().0;
let fourier_scratch =
StackReq::try_new_aligned::<c64>(glwe_size.0 * fourier_polynomial_size, align)?;
let fourier_scratch_single = StackReq::try_new_aligned::<c64>(fourier_polynomial_size, align)?;
let substack3 = fft.forward_scratch()?;
let substack2 = substack3.try_and(fourier_scratch_single)?;
let substack1 = substack2.try_and(standard_scratch)?;
let substack0 = StackReq::try_any_of([
substack1.try_and(standard_scratch)?,
fft.backward_scratch()?,
])?;
substack0.try_and(fourier_scratch)
}
/// Perform the external product of `ggsw` and `glwe`, and adds the result to `out`.
#[cfg_attr(__profiling, inline(never))]
pub fn add_external_product_assign<Scalar, InputGlweCont>(
mut out: GlweCiphertextMutView<'_, Scalar>,
ggsw: FourierGgswCiphertextView<'_>,
glwe: GlweCiphertext<InputGlweCont>,
fft: FftView<'_>,
stack: PodStack<'_>,
) where
Scalar: UnsignedTorus,
InputGlweCont: Container<Element = Scalar>,
{
// we check that the polynomial sizes match
debug_assert_eq!(ggsw.polynomial_size(), glwe.polynomial_size());
debug_assert_eq!(ggsw.polynomial_size(), out.polynomial_size());
// we check that the glwe sizes match
debug_assert_eq!(ggsw.glwe_size(), glwe.glwe_size());
debug_assert_eq!(ggsw.glwe_size(), out.glwe_size());
let align = CACHELINE_ALIGN;
let fourier_poly_size = ggsw.polynomial_size().to_fourier_polynomial_size().0;
// we round the input mask and body
let decomposer = SignedDecomposer::<Scalar>::new(
ggsw.decomposition_base_log(),
ggsw.decomposition_level_count(),
);
let (mut output_fft_buffer, mut substack0) =
stack.make_aligned_raw::<c64>(fourier_poly_size * ggsw.glwe_size().0, align);
// output_fft_buffer is initially uninitialized, considered to be implicitly zero, to avoid
// the cost of filling it up with zeros. `is_output_uninit` is set to `false` once
// it has been fully initialized for the first time.
let output_fft_buffer = &mut *output_fft_buffer;
let mut is_output_uninit = true;
{
// ------------------------------------------------------ EXTERNAL PRODUCT IN FOURIER DOMAIN
// In this section, we perform the external product in the fourier domain, and accumulate
// the result in the output_fft_buffer variable.
let (mut decomposition, mut substack1) = TensorSignedDecompositionLendingIter::new(
glwe.as_ref()
.iter()
.map(|s| decomposer.closest_representable(*s)),
DecompositionBaseLog(decomposer.base_log),
DecompositionLevelCount(decomposer.level_count),
substack0.rb_mut(),
);
// We loop through the levels (we reverse to match the order of the decomposition iterator.)
ggsw.into_levels().rev().for_each(|ggsw_decomp_matrix| {
// We retrieve the decomposition of this level.
let (glwe_level, glwe_decomp_term, mut substack2) =
collect_next_term(&mut decomposition, &mut substack1, align);
let glwe_decomp_term =
GlweCiphertextView::from_container(&*glwe_decomp_term, ggsw.polynomial_size());
debug_assert_eq!(ggsw_decomp_matrix.decomposition_level(), glwe_level);
// For each level we have to add the result of the vector-matrix product between the
// decomposition of the glwe, and the ggsw level matrix to the output. To do so, we
// iteratively add to the output, the product between every line of the matrix, and
// the corresponding (scalar) polynomial in the glwe decomposition:
//
// ggsw_mat ggsw_mat
// glwe_dec | - - - - | < glwe_dec | - - - - |
// | - - - | x | - - - - | | - - - | x | - - - - | <
// ^ | - - - - | ^ | - - - - |
//
// t = 1 t = 2 ...
izip!(
ggsw_decomp_matrix.into_rows(),
glwe_decomp_term.as_polynomial_list().iter()
)
.for_each(|(ggsw_row, glwe_poly)| {
let (mut fourier, substack3) = substack2
.rb_mut()
.make_aligned_raw::<c64>(fourier_poly_size, align);
// We perform the forward fft transform for the glwe polynomial
let fourier = fft
.forward_as_integer(
FourierPolynomialMutView { data: &mut fourier },
glwe_poly,
substack3,
)
.data;
// Now we loop through the polynomials of the output, and add the
// corresponding product of polynomials.
update_with_fmadd(
output_fft_buffer,
ggsw_row.data(),
fourier,
is_output_uninit,
fourier_poly_size,
);
// we initialized `output_fft_buffer, so we can set this to false
is_output_uninit = false;
});
});
}
// -------------------------------------------- TRANSFORMATION OF RESULT TO STANDARD DOMAIN
// In this section, we bring the result from the fourier domain, back to the standard
// domain, and add it to the output.
//
// We iterate over the polynomials in the output.
if !is_output_uninit {
izip!(
out.as_mut_polynomial_list().iter_mut(),
output_fft_buffer
.into_chunks(fourier_poly_size)
.map(|slice| FourierPolynomialView { data: slice }),
)
.for_each(|(out, fourier)| {
fft.add_backward_as_torus(out, fourier, substack0.rb_mut());
});
}
}
#[cfg_attr(__profiling, inline(never))]
fn collect_next_term<'a, Scalar: UnsignedTorus>(
decomposition: &mut TensorSignedDecompositionLendingIter<'_, Scalar>,
substack1: &'a mut PodStack,
align: usize,
) -> (
DecompositionLevel,
dyn_stack::DynArray<'a, Scalar>,
PodStack<'a>,
) {
let (glwe_level, _, glwe_decomp_term) = decomposition.next_term().unwrap();
let (glwe_decomp_term, substack2) = substack1.rb_mut().collect_aligned(align, glwe_decomp_term);
(glwe_level, glwe_decomp_term, substack2)
}
/// # Safety
///
/// - `is_x86_feature_detected!("avx512f")` must be true.
#[cfg(all(
feature = "nightly-avx512",
any(target_arch = "x86_64", target_arch = "x86")
))]
#[target_feature(enable = "avx512f")]
unsafe fn update_with_fmadd_avx512(
output_fourier: &mut [c64],
ggsw_poly: &[c64],
fourier: &[c64],
is_output_uninit: bool,
) {
let n = output_fourier.len();
debug_assert_eq!(n, ggsw_poly.len());
debug_assert_eq!(n, fourier.len());
debug_assert_eq!(n % 4, 0);
let out = output_fourier.as_mut_ptr();
let lhs = ggsw_poly.as_ptr();
let rhs = fourier.as_ptr();
// 4×c64 per register
if is_output_uninit {
for i in 0..n / 4 {
let i = 4 * i;
let ab = _mm512_loadu_pd(lhs.add(i) as _);
let xy = _mm512_loadu_pd(rhs.add(i) as _);
let aa = _mm512_unpacklo_pd(ab, ab);
let bb = _mm512_unpackhi_pd(ab, ab);
let yx = _mm512_permute_pd::<0b01010101>(xy);
_mm512_storeu_pd(
out.add(i) as _,
_mm512_fmaddsub_pd(aa, xy, _mm512_mul_pd(bb, yx)),
);
}
} else {
for i in 0..n / 4 {
let i = 4 * i;
let ab = _mm512_loadu_pd(lhs.add(i) as _);
let xy = _mm512_loadu_pd(rhs.add(i) as _);
let aa = _mm512_unpacklo_pd(ab, ab);
let bb = _mm512_unpackhi_pd(ab, ab);
let yx = _mm512_permute_pd::<0b01010101>(xy);
_mm512_storeu_pd(
out.add(i) as _,
_mm512_fmaddsub_pd(
aa,
xy,
_mm512_fmaddsub_pd(bb, yx, _mm512_loadu_pd(out.add(i) as _)),
),
);
}
}
}
/// # Safety
///
/// - `is_x86_feature_detected!("fma")` must be true.
#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
#[target_feature(enable = "fma")]
unsafe fn update_with_fmadd_fma(
output_fourier: &mut [c64],
ggsw_poly: &[c64],
fourier: &[c64],
is_output_uninit: bool,
) {
let n = output_fourier.len();
debug_assert_eq!(n, ggsw_poly.len());
debug_assert_eq!(n, fourier.len());
debug_assert_eq!(n % 4, 0);
let out = output_fourier.as_mut_ptr();
let lhs = ggsw_poly.as_ptr();
let rhs = fourier.as_ptr();
// 2×c64 per register
if is_output_uninit {
for i in 0..n / 2 {
let i = 2 * i;
let ab = _mm256_loadu_pd(lhs.add(i) as _);
let xy = _mm256_loadu_pd(rhs.add(i) as _);
let aa = _mm256_unpacklo_pd(ab, ab);
let bb = _mm256_unpackhi_pd(ab, ab);
let yx = _mm256_permute_pd::<0b0101>(xy);
_mm256_storeu_pd(
out.add(i) as _,
_mm256_fmaddsub_pd(aa, xy, _mm256_mul_pd(bb, yx)),
);
}
} else {
for i in 0..n / 2 {
let i = 2 * i;
let ab = _mm256_loadu_pd(lhs.add(i) as _);
let xy = _mm256_loadu_pd(rhs.add(i) as _);
let aa = _mm256_unpacklo_pd(ab, ab);
let bb = _mm256_unpackhi_pd(ab, ab);
let yx = _mm256_permute_pd::<0b0101>(xy);
_mm256_storeu_pd(
out.add(i) as _,
_mm256_fmaddsub_pd(
aa,
xy,
_mm256_fmaddsub_pd(bb, yx, _mm256_loadu_pd(out.add(i) as _)),
),
);
}
}
}
/// # Safety
///
/// - if `is_output_uninit` is false, `output_fourier` must not hold any uninitialized values.
unsafe fn update_with_fmadd_scalar(
output_fourier: &mut [c64],
ggsw_poly: &[c64],
fourier: &[c64],
is_output_uninit: bool,
) {
if is_output_uninit {
// we're writing to output_fft_buffer for the first time
// so its contents are uninitialized
izip!(output_fourier, ggsw_poly, fourier).for_each(|(out_fourier, lhs, rhs)| {
*out_fourier = lhs * rhs;
});
} else {
// we already wrote to output_fft_buffer, so we can assume its contents are
// initialized.
izip!(output_fourier, ggsw_poly, fourier).for_each(|(out_fourier, lhs, rhs)| {
*out_fourier += lhs * rhs;
});
}
}
#[cfg_attr(__profiling, inline(never))]
pub(crate) fn update_with_fmadd(
output_fft_buffer: &mut [c64],
lhs_polynomial_list: &[c64],
fourier: &[c64],
is_output_uninit: bool,
fourier_poly_size: usize,
) {
#[allow(clippy::type_complexity)]
let ptr_fn = || -> unsafe fn(&mut [c64], &[c64], &[c64], bool) {
#[cfg(all(
feature = "nightly-avx512",
any(target_arch = "x86_64", target_arch = "x86")
))]
if is_x86_feature_detected!("avx512f") {
return update_with_fmadd_avx512;
}
#[cfg(any(target_arch = "x86_64", target_arch = "x86"))]
if is_x86_feature_detected!("fma") {
return update_with_fmadd_fma;
}
update_with_fmadd_scalar
};
let ptr = ptr_fn();
izip!(
output_fft_buffer.into_chunks(fourier_poly_size),
lhs_polynomial_list.into_chunks(fourier_poly_size)
)
.for_each(|(output_fourier, ggsw_poly)| {
unsafe { ptr(output_fourier, ggsw_poly, fourier, is_output_uninit) };
});
}
/// Return the required memory for [`cmux`].
pub fn cmux_scratch<Scalar>(
glwe_size: GlweSize,
polynomial_size: PolynomialSize,
fft: FftView<'_>,
) -> Result<StackReq, SizeOverflow> {
add_external_product_assign_scratch::<Scalar>(glwe_size, polynomial_size, fft)
}
/// This cmux mutates both ct1 and ct0. The result is in ct0 after the method was called.
pub fn cmux<Scalar: UnsignedTorus>(
ct0: GlweCiphertextMutView<'_, Scalar>,
mut ct1: GlweCiphertextMutView<'_, Scalar>,
ggsw: FourierGgswCiphertextView<'_>,
fft: FftView<'_>,
stack: PodStack<'_>,
) {
izip!(ct1.as_mut(), ct0.as_ref(),).for_each(|(c1, c0)| {
*c1 = c1.wrapping_sub(*c0);
});
add_external_product_assign(ct0, ggsw, ct1, fft, stack);
}