As defined by Tymoczko 2008 ("Scale Theory, Serial Theory and Voice Leading") https://onlinelibrary.wiley.com/doi/10.1111/j.1468-2249.2008.00257.x, the scalar interval matrix represents the "rotations" of a set, transposed to begin on 0, in its columns. Its nth row represents the specific intervals which represent its generic interval of size n.
Examples
diatonic_modes <- sim(c(0, 2, 4, 5, 7, 9, 11))
print(diatonic_modes)
#> [,1] [,2] [,3] [,4] [,5] [,6] [,7]
#> [1,] 0 0 0 0 0 0 0
#> [2,] 2 2 1 2 2 2 1
#> [3,] 4 3 3 4 4 3 3
#> [4,] 5 5 5 6 5 5 5
#> [5,] 7 7 7 7 7 7 6
#> [6,] 9 9 8 9 9 8 8
#> [7,] 11 10 10 11 10 10 10
miyakobushi_modes <- sim(c(0, 1, 5, 7, 8)) # rows show trivalence
print(miyakobushi_modes)
#> [,1] [,2] [,3] [,4] [,5]
#> [1,] 0 0 0 0 0
#> [2,] 1 4 2 1 4
#> [3,] 5 6 3 5 5
#> [4,] 7 7 7 6 9
#> [5,] 8 11 8 10 11