#  This function selects one element at random from the given vector.
#  The result is a scalar.  The argument vector must have at least one
#  element.

select = function (x)
{
  local (n);

  x = vector (x);
  n = x.ne;

  if (!n)
  {
    message ("run time error: Can't select from zero length vector.");
    exception ();
  }

  return x [floor (rand()*n) + 1];
};