Block diagonal matrix.
DB = DiagBlockMat(A1,A2,...,An)
Create the block diagonal matrix DB from the matrices A1, A2,...,An
/ A1 0 0 ... 0 \
| 0 A2 0 : |
DB = | 0 0 A3 |
| : . 0 |
\ 0 ... 0 An /
Package: divand