Transform a chain and drop excess, internal function
reduce_chains_simple.RdTransform a chain and drop excess, internal function.
Details
Given one or more chains corresponding to a common eigenvalue,
reduce_chains_simple transforms the chains so that redundant
eigenvectors are removed. In the process, the heights of some chains
may decrease and the number of chains may be reduced, too.
If sort == TRUE the function reorders the chains so that their
lengths are in decreasing order. However, the algorithm depends on
this being done, so this argument should be used when the chains are
known to be already sorted.
I wrote this function as part of the support for chains of
multi-companion matrices associated with the 0 eigenvalue. When
chains specified via the top left mo.col x mo.col subchains are
extended to chains of the top left mo x mo corner the
(extended) eigenvectors may not be linearly independent.