function getUnpackedMatrixTextureShapeWidthHeight(rows, columns) {
    return [
        columns,
        rows
    ];
}
Single texels contain only values from the same batch, and from adjacent
rows and columns.

This is how the shader encodes a tensor with shape = [2, 3, 5]
(indices are [batch, row, col]).

000|001   002|003   004|xxx   020|021   022|023   024|xxx
-------   -------   -------   -------   -------   -------
010|011   012|013   014|xxx   xxx|xxx   xxx|xxx   xxx|xxx

100|101   102|103   104|xxx   120|121   122|123   124|xxx
-------   -------   -------   -------   -------   -------
110|111   112|113   114|xxx   xxx|xxx   xxx|xxx   xxx|xxx