what is the current state of the art in fast and parallel matrix in-place transposition?I would be very happy, if I could be given some pseudocode for this problem. As far as I could find papers, they do not include very detailed descriptions.Thanks!PS:Of course, we do not restrict to square matrices, but rather arbitrary rectangular matrices. Their memory layout is usually a linear sequence of entries in the memory (say, as in C) and it is a highly non-trivial task to convert this data block in-place/in-situ to the sequence that corresponds to the transposed matrix.Some information can be found in this wikipedia article, whose references I did not find to be very helpful though: Wikipedia Entry.
parallelizable fast matrix in-place transposition
ds.algorithms;co.combinatorics;ds.data structures;dc.parallel comp
Sorry, no pseudocode, but a recent paper with a fast parallel algorithm, to appear in ACM Transactions on Mathematical Software:@Article{Gustavson:2011:PCE,  author =       Fred Gustavson and Lars Karlsson and Bo K{\aa}gstr{\o}m,  title =        Parallel and Cache-Efficient In-Place Matrix Storage Format                  Conversion,  journal =      {ACM} Transactions on Mathematical Software,  accepted =     8 July 2010,  upcoming =     true,   abstract =                       Techniques and algorithms for efficient in-place                  conversion to and from standard and blocked matrix                  storage formats are described. Such functionality is                  required by numerical libraries that use different                  data layouts internally. Parallel algorithms and a                  software package for in-place matrix storage format                  conversion based on in-place matrix transposition are                  presented and evaluated. A new algorithm for in-place                  transposition which efficiently determines the structure                  of the transposition permutation a priori is one of the                  key ingredients. It enables effective load balancing in                  a parallel environment.,}Here is the journal page, and here is a pdf version of the paper.I hope this can be useful.