Return a symbolic object with the following internal format:
$M
[1] 5
$var.types
[1] "$C" "$H" "$I" "$H" "$C"
$var.length
[1] 1 5 2 3 1
$var.names
[1] "F1" "F2" "F3" "F4" "F5"
$obj.data.vector
F1 M1 M2 M3 M4 M5 F3 F3.1 M1.1 M2.1 M3.1 F5
Case4 -2.1 0.4 0.1 0.1 0.1 0.3 0 2 0.9 0 0.1 0