Description

   The seed48 function initializes the random-number generator.
   You can use this function in your program before calling the
   drand48, lrand48, or mrand48 functions. (Although it is not
   recommended practice, constant default initializer values are
   supplied automatically if you call drand48, lrand48, or mrand48
   without calling an initialization function).

   The seed48 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 initializer function seed48:

   o  Sets the value of Xi to the 48-bit value specified in the
      array pointed to by seed_16v.

   o  Returns a pointer to a 48-bit internal buffer that contains
      the previous value of Xi, used only by seed48.

   The returned pointer allows you to restart the pseudorandom
   sequence at a given point. Use the pointer to copy the previous
   Xi value into a temporary array. To resume where the original
   sequence left off, you can call seed48 with a pointer to this
   array.

   See also drand48, lrand48, and mrand48.