Important: The linalg package has been deprecated. Use the superseding command LinearAlgebra[SubMatrix], instead.

- For information on migrating linalg code to the new packages, see examples/LinearAlgebraMigration.

The call submatrix(A, Rrange, Crange) returns the submatrix of A selected by the row range Rrange and the column range Crange.

The call submatrix(A, Rlist, Clist) returns the matrix whose (i,j)th element is A[Rlist[i], Clist[j]].

These calling methods can be combined, so for instance the call submatrix(A, Rlist, Crange) is valid, and will return the submatrix of A with rows from Rlist and columns from Crange.

The command with(linalg,submatrix) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{linalg}\right)\:$

$A≔\mathrm{array}\left(\left[\left[1\,2\,3\right]\,\left[4\,x\,6\right]\right]\right)$

$A≔\left[\begin{array}{ccc}1& 2& 3\\ 4& x& 6\end{array}\right]$

$\mathrm{submatrix}\left(A\,1..2\,2..3\right)$

$\left[\begin{array}{cc}2& 3\\ x& 6\end{array}\right]$

$\mathrm{submatrix}\left(A\,\left[2\,1\right]\,\left[2\,1\right]\right)$

$\left[\begin{array}{cc}x& 4\\ 2& 1\end{array}\right]$

$\mathrm{submatrix}\left(A\,\left[2\,1\right]\,1..2\right)$

$\left[\begin{array}{cc}4& x\\ 1& 2\end{array}\right]$