The band indexing function can be used to construct rtable objects of type Array or Matrix.

As a parameter to the Matrix constructor, this indexing function can take either of the following forms.

1.  The band[b] indexing function specifies that the constructed object is a band Matrix with b non-zero subdiagonals and b non-zero superdiagonals.

2.  The band[b1, b2] indexing function specifies that the constructed object is a band Matrix with b1 non-zero subdiagonals and b2 non-zero superdiagonals.

The values of b1 and b2 are stored separately from the data in the Matrix data structure.

The specification is the same in the construction of an Array.

$M≔\mathrm{Matrix}\left(\left[\left[w\,w\,w\right]\,\left[x\,x\,x\,x\right]\,\left[y\,y\,y\,y\right]\,\left[z\,z\,z\right]\right]\,\mathrm{shape}=\mathrm{band}\left[1,2\right]\,\mathrm{scan}=\mathrm{band}\left[1,2\right]\right)$

$M≔\left[\begin{array}{ccccc}x& y& z& 0& 0\\ w& x& y& z& 0\\ 0& w& x& y& z\\ 0& 0& w& x& y\end{array}\right]$