gcc/testsuite/gfortran.dg/gamma_5.f90

   1 ! { dg-do run }
   2 ! PR 33683 - we used to pick up the wrong gamma function
   3 ! from the library on some systems.
   4 program main
   5   implicit none
   6   integer, parameter :: n_max = 20
   7   double precision, dimension(0:n_max) :: c
   8   double precision :: pi
   9   integer :: n
  10   double precision :: td, xd
  11   real :: ts,xs
  12
  13   pi = 4 * atan(1.d0)
  14   c(0) = 1.
  15   do n=1, n_max
  16      c(n) = (2*n-1)*c(n-1)*0.5d0
  17   end do
  18
  19   do n=1, n_max
  20      xs = n + 0.5
  21      xd = n + 0.5d0
  22      td = c(n)*sqrt(pi)
  23      ts = c(n)*sqrt(pi)
  24      if (abs(gamma(xs)-ts)/ts > 9e-6) call abort
  25      if (abs(gamma(xd)-td)/td > 5e-14) call abort
  26   end do
  27   call tst_s(2.3, gamma(2.3))
  28   call tst_s(3.7, gamma(3.7))
  29   call tst_s(5.5, gamma(5.5))
  30   call tst_d(4.2d0, gamma(4.2d0))
  31   call tst_d(8.1d0, gamma(8.1d0))
  32 contains
  33   subroutine tst_s(a, b)
  34     real :: a, b
  35     if (abs(gamma(a) - b)/b > 1e-6) call abort
  36   end subroutine tst_s
  37
  38   subroutine tst_d(a, b)
  39     double precision :: a,b
  40     if (abs(gamma(a) - b)/b > 5e-14) call abort
  41   end subroutine tst_d
  42 end program main