BlockDiagonalMatrix

BlockDiagonalMatrix[{d1, d2, ...}] represents the block diagonal matrix with diagonal blocks di as a structured array.

BlockDiagonalMatrix[mat] converts the block diagonal matrix mat to a structured array.

Examples

Create a block diagonal matrix:

BlockDiagonalMatrix[{{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}]

View as normal matrix:

Normal[BlockDiagonalMatrix[{{{1, 0}, {0, 1}}, {{2}}}]]

Please visit the official Wolfram Language Reference for more details.