schurmod(x, indexes=<see below>, vectors=<see below>)
schur.Matrix
.
indexes = c(i,j)
, then the block or element
in row
i
is moved to row
j
by a sequence of transpositions between
adjacents blocks or elements.
x
. The default is to update and return the Schur
vectors.
schur.Matrix
containing the reordered Schur form and
(optionally) the corresponding Schur vectors.
Based on the functions dtrexc and ztrexc from Lapack (Anderson et al. 1994).
Anderson, E., et al. (1994). LAPACK User's Guide, 2nd edition, SIAM, Philadelphia.
Does not return the proper ordering in all cases. A bug report will be filed with the Lapack developers.
n <- 9 x <- Matrix( rnorm( n*n, sd = 100), nrow = n, ncol = n) schur.x <- schur(x) # schur factorization schur.x <- schurmod(schur.x, indexes = c(1,n)) # reordered factorization