Question

我正在尝试学习如何在R中使用fortran代码。我能够关注this tutorial。现在，我正在尝试将其作为基础加this fortran program to calculate pi。我使用以下代码创建了一个文件Fpi.f90：

private void tabControl1_Selecting(object sender, TabControlCancelEventArgs e)
{
    if (tabControl1.SelectedTab == tabPage1)
    {
        //Attach only once
        if (tabPage1.HasChildren)
            return;
        myDialog1 dg = new myDialog1();
        dg.TopLevel = false;
        dg.Dock = DockStyle.Fill;
        dg.Parent = tabPage1;
        dg.Show();
    }
    else if (tabControl1.SelectedTab == tabPage2)
    {
        if (tabPage2.HasChildren)
            return;
        myDialog2 dg = new myDialog2();
        dg.TopLevel = false;
        dg.Dock = DockStyle.Fill;
        dg.Parent = tabPage2;
        dg.Show();
    }
    else if (tabControl1.SelectedTab == tabPage3)
    {
       //and so on
    }
}

当

subroutine pi(avepi, DARTS, ROUNDS)
double precision, intent(out)   ::  avepi
integer, intent(in)             ::  DARTS, ROUNDS
integer                         ::  MASTER, rank, i, n
integer, allocatable            ::  seed(:)
double precision                ::  pi_est, homepi, pirecv, pisum

! we set it to zero in the sequential run
rank = 0
! initialize the random number generator
! we make sure the seed is different for each task
call random_seed()
call random_seed(size = n)
allocate(seed(n))
seed = 12 + rank*11
call random_seed(put=seed(1:n))
deallocate(seed)

avepi = 0
do i = 0, ROUNDS-1
  pi_est = dboard(DARTS)
  ! calculate the average value of pi over all iterations
  avepi = ((avepi*i) + pi_est)/(i + 1)
end do
end subroutine pi


double precision function dboard(darts)
integer, intent(in)           :: darts
double precision              :: x_coord, y_coord
integer                       :: score, n

score = 0
do n = 1, darts
  call random_number(x_coord)
  call random_number(y_coord)

  if ((x_coord**2 + y_coord**2) <= 1.0d0) then
  score = score + 1
  end if
end do
dboard = 4.0d0*score/darts

end function

我做错了什么？

将$ R CMD SHLIB ./Fortran/Fpi.f90 gfortran -fpic -g -O2 -fstack-protector-strong -c Fortran/Fpi.f90 -o Fortran/Fpi.o Fortran/Fpi.f90:22.15: pi_est = dboard(DARTS) 1 Error: Return type mismatch of function 'dboard' at (1) (REAL(4)/REAL(8)) /usr/lib/R/etc/Makeconf:161: recipe for target 'Fortran/Fpi.o' failed make: *** [Fortran/Fpi.o] Error 1添加到double precision :: dboard后，我收到了不同的错误。

pi

Answer 1

您不使用implicit none。那太糟糕了！由于隐式输入dboard被认为是默认真实的pi。

将其声明为双精度，或者如果可能，使用R，使用模块。接口块也可用于在dboard内声明pi。

在R中使用Fortran子程序？错误：返回类型不匹配

1 个答案: