Progress Report—11/13 宗慶
Problem Statement Find kernels of large and sparse linear systems over GF(2)
Well-Known Solutions Block Lanczos Algorithm Block Wiedemann Algorithm
Published in 1994 Solving Homogeneous Linear Equations Over GF(2) via Block Wiedmemann Algorithm by Don Coppersmith Don Coppersmith proposed a block version of the Wiedemann algorithm which take advantage of the ability to perform simultaneous operations on block of vectors.
Wiedemann algorithm Based on the fact that when a square matrix is repeatedly applied to a vector, the resulting vector sequence is linear recursive.
Advantages of Blocking Parallel implementation Faster sequential running time Better probability of success [Villard 1997]
Block Wiedemann Algorithm
Three-tier Parallelism on Cell blades SIMD on SPE Heterogeneous Multi-cores per node MPI between nodes
Available Resources Implementation of block Lanczos algorithm openmp LinBox A C++ template library for exact, high- performance linear algebra computation with dense, sparse, and structured matrices over the integers and over finite fields. Many papers….. Cell Blades Connected via Ethernet ITRI plan to purchase Infiniband
Challenges awaits me Symbolic computation Map algebra to computer Data structures How to represent data efficiently Many similar block Wiedemann algorithms