Part(s) of almost block-diagonal matrix
[nb,rows,ncols,last,blocks] = bkbrk(blokmat)
bkbrk(blokmat)
[nb,rows,ncols,last,blocks] = bkbrk(blokmat) returns
the details of the almost block-diagonal matrix contained in
blokmat, with rows and
last
nb-vectors, and blocks a matrix of size
[sum(rows),ncols].
This utility program is not likely to be of interest to the casual user. It is
used in slvblk to decode the information,
provided by spcol, about a spline collocation
matrix in an almost block diagonal form especially suited for splines. But
bkbrk can also decode the almost block-diagonal form used in
[1].
bkbrk(blokmat) returns nothing, but the
details are printed out. This is of use when trying to understand what went wrong
with such a matrix.
[1] C. de Boor and R. Weiss. “SOLVEBLOK: A package for solving almost block diagonal linear systems.” ACM Trans. Mathem. Software 6 (1980), 80–87.