Description

   The nrand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   The nrand48 function returns nonnegative, long integers uniformly
   distributed over the range of y values, such that 0 
   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The nrand48 function requires that the calling program pass an
   array as the xsubi argument, which for the first call must be
   initialized to the initial value of the pseudorandom-number
   sequence. Unlike the drand48 function, it is not necessary to
   call an initialization function prior to the first call.

   By using different arguments, the nrand48 function allows
   separate modules of a large program to generate several
   independent sequences of pseudorandom numbers. For example, the
   sequence of numbers that one module generates does not depend
   upon how many times the functions are called by other modules.