Applied Parallel Computing. State of the Art in Scientific Computing

Volume 4699 of the series Lecture Notes in Computer Science pp 560-569

In-Place Transposition of Rectangular Matrices

  • Fred G. GustavsonAffiliated withIBM T. J. Watson Research Center, Yorktown Heights, NY 10598
  • , Tadeusz SwirszczAffiliated withFaculty of Mathematics and Information Science, Warsaw University of Technology, Warsaw

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We present a new Algorithm for In-Place Rectangular Transposition of an m by n matrix A that is efficient. In worst case it is O(N logN) where N = mn. It uses a bit-vector of size IWORK words to further increase its efficiency. When IWORK=0 no extra storage is used. We also review some of the other existing algorithms for this problem. These contributions were made by Gower, Windley, Knuth, Macleod, Laffin and Brebner (ACM Alg. 380), Brenner (ACM Alg. 467), and Cate and Twigg (ACM Alg. 513). Performance results are given and they are compared to an Out-of-Place Transposition algorithm as well as ACM Algorithm 467.