Question

有人可以帮我解决以下问题吗？我是Fortran的新手，我正在尝试使用GCC for Windows运行以下内容。

program jacobi
implicit none
double precision, dimension(:,:), allocatable :: u, u_n
double precision :: Res_2, Res_inf
integer :: i,j,mesh,unit
mesh=64

Res_2=0
allocate(u(0:mesh,0:mesh))
allocate(u_n(0:mesh,0:mesh))
u=0
u_n=0
u(:,0)=1
u_n(:,0)=1
unit=12

open(unit, file="array.txt", access='append', status='old')

do while (Res_2>1D-10)
    Res_2=0
    do (i=1,mesh-1)
        do (j=1,mesh-1)
            u(i,j)=0.25D0*(u_n(i+1,j)+u_n(i-1,j)+u_n(i,j-1))
        end do
    end do
    Res_inf=-4D0*maxval((u-u_n))
    do (i=1,mesh-1)
        do (j=1,mesh-1)
            Res_2=Res_2+(-4D0*(u(i,j)-u_n(i,j)))**2
        end do
    end do
    Res_2=sqrt(Res_2)
    write(1,*) Res_2
end do
close(unit)

end program jacobi

编译时我一直收到这些错误：

jacobi.f95:21.2:

  do (i=1,mesh-1)
  1
Error: Unclassifiable statement at (1)
jacobi.f95:22.3:

   do (j=1,mesh-1)
   1
Error: Unclassifiable statement at (1)
jacobi.f95:25.5:

  end do
     1
Error: Expecting END PROGRAM statement at (1)
jacobi.f95:27.2:

我使用do循环错了吗？我是否错误地声明了变量'i，j'？

Answer 1

您的陈述中的括号，例如

do (i=1,mesh-1)

是不可接受的，Fortran中的正确形式是

do i=1,mesh-1

未能看到（有效）do语句后，编译器会在找到无法匹配的end do语句时抱怨。修复do语句，关于期望end program语句的错误应该消失。

Fortran编译错误：不可分类的语句

1 个答案: