rand

Generates a pseudo-random number.

Prototype

	function rand (
	)

	return_val [1] :  integer

Return value

Returns a pseudo-random integral value in the range of 0 <= return_val <= 32766.

Description

This function is NCL's original random number generator. To generate many different random numbers, the user must loop over the rand function the appropriate number of times. This may be inefficient if a large sample is required.

See Also

srand random_setallseed, random_chi, random_gamma, random_normal, random_uniform

Examples

Example 1

Generates 100 pseudo-random integers:

   int_random = new(100, integer)
   
   do n = 0, 99
      int_random(n) = rand()
   end do

Generate a three dimensional array of random numbers ranging from -5.0 to +5.0 (type float). Explicitly set the seed via srand:

   klev =  10
   nlat =  64
   mlon = 128

   low  = -5.0
   high =  5.0
   con  = (high - low) / 32766.0      ; 32766.0 forces a 0.0 to 1.0 range

   x    = new((/klev, nlat, mlon/), float)

   srand(123456789)

   do k = 0, klev - 1
     do n = 0, nlat - 1
       do m = 0, mlon - 1
         x(k, n, m) = low + con * rand()
       end do
     end do
   end do