gcc/testsuite/gfortran.dg/random_3.f90

   1 ! { dg-do run }
   2 ! { dg-require-effective-target fortran_large_real }
   3 ! Check that the random_seed for real(10) exists and that
   4 ! real(8) and real(10) random number generators
   5 ! return the same sequence of values.
   6 ! Mostly copied from random_2.f90
   7 program random_3
   8   integer,parameter :: k = selected_real_kind (precision (0.0_8) + 1)
   9
  10   integer, dimension(:), allocatable :: seed
  11   real(kind=8), dimension(10) :: r8
  12   real(kind=k), dimension(10) :: r10
  13   real, parameter :: delta = 1.d-10
  14   integer n
  15
  16   ! Run the test only if real(10) is available. With the current
  17   ! xorshift1024* PRNG the real(16) generator uses two uint64_t values
  18   ! for every real(16) value generated, and hence the sequences won't
  19   ! be the same as with real(4,8,10).
  20   if (k == 10) then
  21      call random_seed (size=n)
  22      allocate (seed(n))
  23      call random_seed (get=seed)
  24      ! Test both array valued and scalar routines.
  25      call random_number(r8)
  26      call random_number (r8(10))
  27
  28      ! Reset the seed and get the real(8) values.
  29      call random_seed (put=seed)
  30      call random_number(r10)
  31      call random_number (r10(10))
  32
  33      if (any ((r8 - r10) .gt. delta)) call abort
  34   end if
  35 end program random_3