src/numtheory/cl_nt_nextprobprime.cc

   1 // nextprobprime().
   2
   3 // General includes.
   4 #include "cl_sysdep.h"
   5
   6 // Specification.
   7 #include "cl_numtheory.h"
   8
   9
  10 // Implementation.
  11
  12 #include "cl_real.h"
  13
  14 const cl_I nextprobprime (const cl_R& x)
  15 {
  16         if (minusp(x))
  17                 return 2;
  18         // Now x >= 0.
  19         var cl_I n = ceiling1(x);
  20         if (n <= 2)
  21                 return 2;
  22         // Now n>=3.
  23         if (evenp(n))
  24                 n = n+1;
  25         // Now n>=3 odd.
  26         loop {
  27                 if (isprobprime(n))
  28                         return n;
  29                 n = n+2;
  30         }
  31 }