$R: Row Index of Left Hand Side Array

The global variable $R is the current row number of the left-hand side matrix in array operations

DIMENSION matrix(2,3) ! 2 rows x 3 columns matrix example ( Arrays)
matrix = $R

1	1	1
2	2	2

! Use along with left-hand side column index $C is possible:
matrix = $R + $C/10

1.1	1.2	1.3
2.1	2.2	2.3

! $C, $R, and left-hand side linear index $:
matrix = 10*$R + $C + $/100

11.01	12.02	13.03
21.04	22.05	23.06

! inline_loop to find the

for each row of M33

M33

Q33

REAL :: n=3, M33(3,3), Q33(3,3) ! define two 3x3 matrices
M33 = $ ! sets M33 to 1, 2, .., 9
Q33 = +( M33($R, 1: $C) ) ! sums each row from 1 to $C