HP 48gII - Manual (Page 323)

Page 10-23
In RPN mode, you need to list the matrix in the stack, and the activate function
ROW, i.e., @@@A@@@ ROW. The figure below shows the RPN stack before
and after the application of function ROW.
In this result, the first row occupies the highest stack level after decomposition,
and stack level 1 is occupied by the number of rows of the original matrix.
The matrix does not survive decomposition, i.e., it is no longer available in the
stack.
Function ROW→
Function ROW → has the opposite effect of the function → ROW, i.e., given n
vectors of the same length, and the number n, function ROW builds a
matrix by placing the input vectors as rows of the resulting matrix. Here is an
example in ALG mode. The command used was:
ROW ([1,2,3],[4,5,6],[7,8,9],3)
In RPN mode, place the n vectors in stack levels n+1, n, n-1,…,2, and the
number n in stack level 1. With this set up, function ROW places the
vectors as rows in the resulting matrix. The following figure shows the RPN
stack before and after using function ROW .