Spline Toolbox

bkbrk

Part(s) of an almost block-diagonal matrix

Syntax

• [nb,rows,ncols,last,blocks] = bkbrk(blokmat)
  bkbrk(blokmat)
  

Description

[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.

See Also

slvblk, spcol

References

[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.

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