On Transposing Large 2nx 2nMatrices

This correspondence presents two variations on the algorithm of Eklundh for transposing large 2n x 2n matrices. The first variation shows how the number of accesses to secondary storage may be reduced at the expense of an increased amount of data transferred. Formulas for I/O time are derived from which we deduce the disk characteristics under which there is an improvement. The second variation shows that a small amount of additional secondary storage can be used to greatly improve the performance of the algorithm.