HP 50g Graphing Calculator - Manual (Page 322)

Page 10-21
In RPN mode, function CSWP lets you swap the columns of a matrix listed in
stack level 3, whose indices are listed in stack levels 1 and 2. For example, the
following figure shows the RPN stack before and after applying function CSWP
to matrix A in order to swap columns 2 and 3:
As you can see, the columns that originally occupied positions 2 and 3 have
been swapped. Swapping of columns, and of rows (see below), is commonly
used when solving systems of linear equations with matrices. Details of these
operations will be given in a subsequent Chapter.
Manipulating matrices by rows
The calculator provides a menu with functions for manipulating matrices by
operating in their rows. This menu is available through the MTH/MATRIX/
ROW.. sequence: (
„´) shown in the figure below with system flag 117 set
to CHOOSE boxes:
or through the MATRICES/CREATE/ROW sub-menu:
Both approaches will show the same functions: