Section: Elementary Functions
y = ceil(x)
where x is a multidimensional array of numerical type.  The ceil 
function preserves the type of the argument.  So integer arguments 
are not modified, and float arrays return float arrays as 
outputs, and similarly for double arrays.  The ceil function 
is not defined for complex or dcomplex types.
ceil function applied to various
(numerical) arguments.  For integer arguments, the ceil function has
no effect:
--> ceil(3) ans = 3 --> ceil(-3) ans = -3
Next, we take the ceil of a floating point value:
--> ceil(float(3.023)) ans = 4 --> ceil(float(-2.341)) ans = -2
Note that the return type is a float also.  Finally, for a double
type:
--> ceil(4.312) ans = 5 --> ceil(-5.32) ans = -5