This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.

# ArrayFlatten

 ArrayFlatten[{{m11, m12, ...}, {m21, m22, ...}, ...}]creates a single flattened matrix from a matrix of matrices . ArrayFlatten[a, r]flattens out pairs of levels in the array .
• ArrayFlatten requires that the blocks it flattens have dimensions that fit together.
• ArrayFlatten can be used to form block matrices from arrays of blocks.
• For a matrix of matrices, ArrayFlatten[a] yields a matrix whose elements are in the same order as in MatrixForm[a].
• For a tensor with rank , ArrayFlatten[a, r] gives a tensor with rank .
• In ArrayFlatten[{{m11, m12, ...}, {m21, m22, ...}, ...}] all the matrices in the same row must have the same first dimension, and matrices in the same column must have the same second dimension.
• In general, in ArrayFlatten[a, r], all the dimensions of must be equal for each possible value of .
• Elements at level whose array depth is less than are treated as scalars, and are replicated to fill out a rank array of the appropriate dimensions.
Create a block matrix by flattening out a matrix of matrices:
 Out[2]=

Use 0s to represent zero matrices:
 Out[2]=
 Scope   (4)
 Applications   (4)
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