drand48,  erand48,  lrand48,  nrand48,   mrand48,   jrand48,
     srand48,  seed48,  lcong48  - generate uniformly distributed
     pseudo-random numbers


     #include <stdlib.h>

     double drand48(void);

     double erand48(unsigned short int xsubi[3]);

     long int lrand48(void);

     long int nrand48(unsigned short int xsubi[3]);

     long int mrand48(void);

     long int jrand48(unsigned short int xsubi[3]);

     void srand48(long int seedval));

     unsigned short int *seed48(unsignedshortint seed16v [3]);

     void lcong48(unsigned short int param[7]);


     These functions generate  pseudo-random  numbers  using  the
     linear congruential algorithm and 48-bit integer arithmetic.

     The drand48() and erand48()  functions  return  non-negative
     double-precision floating-point values uniformly distributed
     between [0.0, 1.0).

     The lrand48() and nrand48()  functions  return  non-negative
     long integers uniformly distributed between 0 and 2^31.

     The mrand48() and jrand48()  functions  return  signed  long
     integers uniformly distributed between -2^31 and 2^31.

     The srand48(), seed48() and lcong48() functions are initial-
     ization  functions,  one  of  which  should be called before
     using drand48(),  lrand48()  or  mrand49().   The  functions
     erand48(),  nrand48()  and  jrand48() do not require an ini-
     tialization function to be called first.

     All the functions work by generating a  sequence  of  48-bit
     integers, Xi, according to the linear congruential formula:

          Xn+1 = (aXn + c) mod

     The parameter m = 2^48, hence 48-bit integer  arithmetic  is
     performed.   Unless  lcong48()  is called, a and c are given

          a = 0x5DEECE66D
          c = 0xB

     The value  returned  by  any  of  the  functions  drand48(),
     erand48(),  lrand48(),  nrand48(), mrand48() or jrand48() is
     computed by first generating  the  next  48-bit  Xi  in  the
     sequence.  Then the appropriate number of bits, according to
     the type of data item to be returned,  is  copied  from  the
     high-order  bits  of  Xi  and  transformed into the returned

     The functions drand48(), lrand48() and mrand48()  store  the
     last  48-bit  Xi generated in an internal buffer.  The func-
     tions erand48(), nrand48() and jrand48() require the calling
     program  to  provide storage for the successive Xi values in
     the array argument xsubi.  The functions are initialized  by
     placing  the  initial value of Xi into the array before cal-
     ling the function for the first time.

     The initializer function srand48() sets the high  order  32-
     bits  of  Xi to the argument seedval.  The low order 16-bits
     are set to the arbitrary value 0x330E.

     The initializer function seed48() sets the value  of  Xi  to
     the  48-bit  value  specified in the array argument seed16v.
     The previous value of Xi is copied into an  internal  buffer
     and a pointer to this buffer is returned by seed48().

     The initialization function lcong48()  allows  the  user  to
     specify initial values for Xi, a and c.  Array argument ele-
     ments param[0-2]  specify  Xi,  param[3-5]  specify  a,  and
     param[6]  specifies  c.   After lcong48() has been called, a
     subsequent call to either srand48() or seed48() will restore
     the standard values of a and c.


     SVID 3


     These functions are  declared  obsolete  by  SVID  3,  which
     states that rand(3) should be used instead.


     rand(3), random(3)