Matrix M:
     [,1] [,2]
[1,]  4.5  2.9
[2,]  0.7  4.0
Attributes of M:
$dim
[1] 2 2

   c1 c2
r1 34  8
r2 -2 21
$dim
[1] 2 2

$dimnames
$dimnames[[1]]
[1] "r1" "r2"

$dimnames[[2]]
[1] "c1" "c2"


[1] 4.5 0.7 2.9 4.0
[1] 34 -2  8 21
[1] FALSE
[1] FALSE
Are M and A vectors?
TRUE    TRUE 
Matrix M:
[1] 4.5 0.7 2.9 4.0
Matrix A:
[1] 34 -2  8 21