Vectors are not the same as 1d matrices/arrays because a vector does not have direction (i.e. it's not a row vector or a column vector, but will work as either depending on circumstance).

  > all.equal(1:10, matrix(1:10, ncol = 1))
  [1] "Attributes: < target is NULL, current is list >"
  [2] "target is numeric, current is matrix"   
  > all.equal(matrix(1:10, ncol = 1), array(1:10, c(10, 1)))
  [1] TRUE