Merge pull request #4053 from pleroy/L2

An implementation of Nguyễn and Stehlé's L2 algorithm for lattice reduction

documentation/bibliography.bib

@@ -1159,6 +1159,18 @@ @article{Newhall1989
   volume       = {45},
 }
 
+@article{NguyễnStehlé2009,
+  author       = {Nguyễn, Phong Q. and Stehlé, Damien},
+  url          = {https://doi.org/10.1137/070705702},
+  date         = {2009},
+  doi          = {10.1137/070705702},
+  journaltitle = {SIAM Journal on Computing},
+  number       = {3},
+  pages        = {874--903},
+  title        = {An LLL Algorithm with Quadratic Complexity},
+  volume       = {39},
+}
+
 @article{Nievergelt2004,
   author       = {Nievergelt, Yves},
   date         = {2004-12},
@@ -2080,7 +2092,7 @@ @inproceedings{WuZhang1991
 }
 
 @mvbook{Fontenelle1758,
-  author    = {de Fontelle, Bernard},
+  author    = {de Fontenelle, Bernard Le Bouyer},
   publisher = {B.~Brunet},
   date      = {1758/1766},
   doi       = {10.3931/e-rara-25886},

numerics/lattices.hpp

@@ -16,9 +16,15 @@ template<typename Matrix>
   requires two_dimensional<Matrix>
 Matrix LenstraLenstraLovász(Matrix const& L);
 
+// Same convention as above, but using a more efficient algorithm.
+template<typename Matrix>
+  requires two_dimensional<Matrix>
+Matrix NguyễnStehlé(Matrix const& L);
+
 }  // namespace internal
 
 using internal::LenstraLenstraLovász;
+using internal::NguyễnStehlé;
 
 }  // namespace _lattices
 }  // namespace numerics