vmp & svp doc

base2k/src/svp.rs

@@ -0,0 +1,60 @@
+use crate::ffi::svp::{delete_svp_ppol, new_svp_ppol, svp_apply_dft, svp_ppol_t, svp_prepare};
+use crate::scalar::Scalar;
+use crate::{Free, Module, VecZnx, VecZnxDft};
+
+pub struct SvpPPol(pub *mut svp_ppol_t, pub usize);
+
+/// A prepared [crate::Scalar] for [ScalarVectorProduct::svp_apply_dft].
+/// An [SvpPPol] an be seen as a [VecZnxDft] of one limb.
+/// The backend array of an [SvpPPol] is allocated in C and must be freed manually.
+impl SvpPPol {
+    /// Returns the ring degree of the [SvpPPol].
+    pub fn n(&self) -> usize {
+        self.1
+    }
+
+    /// Returns the number of limbs of the [SvpPPol], which is always 1.
+    pub fn limbs(&self) -> usize {
+        1
+    }
+}
+
+impl Free for SvpPPol {
+    fn free(self) {
+        unsafe { delete_svp_ppol(self.0) };
+        let _ = drop(self);
+    }
+}
+
+pub trait ScalarVectorProduct {
+    /// Prepares a [crate::Scalar] for a [ScalarVectorProduct::svp_apply_dft].
+    fn svp_prepare(&self, svp_ppol: &mut SvpPPol, a: &Scalar);
+
+    /// Allocates a new [SvpPPol].
+    fn svp_new_ppol(&self) -> SvpPPol;
+
+    /// Applies the [SvpPPol] x [VecZnxDft] product, where each limb of
+    /// the [VecZnxDft] is multiplied with [SvpPPol].
+    fn svp_apply_dft(&self, c: &mut VecZnxDft, a: &SvpPPol, b: &VecZnx);
+}
+
+impl Module {
+    pub fn svp_prepare(&self, svp_ppol: &mut SvpPPol, a: &Scalar) {
+        unsafe { svp_prepare(self.0, svp_ppol.0, a.as_ptr()) }
+    }
+
+    pub fn svp_new_ppol(&self) -> SvpPPol {
+        unsafe { SvpPPol(new_svp_ppol(self.0), self.n()) }
+    }
+
+    pub fn svp_apply_dft(&self, c: &mut VecZnxDft, a: &SvpPPol, b: &VecZnx) {
+        let limbs: u64 = b.limbs() as u64;
+        assert!(
+            c.limbs() as u64 >= limbs,
+            "invalid c_vector: c_vector.limbs()={} < b.limbs()={}",
+            c.limbs(),
+            limbs
+        );
+        unsafe { svp_apply_dft(self.0, c.0, limbs, a.0, b.as_ptr(), limbs, b.n() as u64) }
+    }
+}