Question

我在FORTRAN中为共轭梯度法编写了一个代码...有一个错误，我无法在工作数小时后解决它！附加的代码是执行CGR的子程序，它是我的主程序的一部分，由2个函数和其他子程序组成。

!                       (C_F2,C2  ,C1  ,C_Fold,IG ,JG ,dCnew,converged)
    SUBROUTINE gcr_Mfree(F2  ,Cnew,Cold,C_Fold,IGG,JGG,x    ,converged)

        !**** FUNCTIONS TO BE SOLVED ****
        ! Generalized Conjugate Residual Algorithm
        ! Solves M*x=b (J*dx=-F)


        ! Use somemodule
        ! Arguments declarations
        IMPLICIT REAL*8 (A-H,O-Z)

        INTEGER :: IGG,JGG
        real*8, dimension(:), ALLOCATABLE :: x
        real*8, intent(out)                 :: converged  !<
        REAL*8, DIMENSION(:,:), ALLOCATABLE :: F2,F22,Cnew,Cold,C_Fold,p,Mp 

        ! Variable declarations
        real*8 :: alpha2,tol  
        real*8, DIMENSION(:),   ALLOCATABLE :: r,b,Mr,F2V,F22V,CnewV,ColdV,C_FoldV
        integer :: i,j,maxiter,AllocateStatus,normr

        MASK = SIZE(F2)
        ALLOCATE(F2V(1:MASK))
        ALLOCATE(CnewV(1:MASK))
        ALLOCATE(ColdV(1:MASK))
        ALLOCATE(C_FoldV(1:MASK))
        !*********** RESHAPING MATRICES TO VECTORS.........
        F2V    = RESHAPE(F2  ,(/MASK/))
        CnewV  = RESHAPE(Cnew,(/MASK/))
        ColdV  = RESHAPE(Cold,(/MASK/))
        C_FoldV = RESHAPE(C_Fold,(/MASK/))

        b       = -F2V                 !(why minus?)
        tol     = 5.E-2
        alpha2  = 1e-6 ! alpha2 is the epsilon in the report!
        maxiter = size(b)

        DEALLOCATE(x)
        ALLOCATE(x(1:maxiter))
        x       = 0.0D0       !GUIdE: ""m2f: x = zeros(maxiter,1)""


        r       = b ! we need this when calculating r_new
        ! normr(1) = norm2(r)                             !!!! Norm


        DO iter=1,maxiter

            !Get preliminary search direction

            DO i=1,iter
                p(:,i) = r
            ENDDO

            ! Approximate the Jacobian(M) residual product
            CnewV = CnewV + alpha2*r
            Cnew = RESHAPE(CnewV,(/IGG,JGG/))

            F22 = CNF2(Cnew,Cold,Fold,DT)
            F22V= RESHAPE(F22V,(/MASK/))

            Mr = (1/alpha2)*(F22V-F2V)      !GUIDE: (The apporximated Jacobian matrix)

            DO i=1,iter
                Mp(:,i) = Mr
            ENDDO

            !! Orthogonalize search direction
            do j=1,iter-1
          !m2f: p(:,iter) = p(:,iter) -  Mp(:,j)'* Mp(:,iter) * p(:,j)
                p(:,iter) = p(:,iter) -  Mp(j,:) * Mp(:,iter) * p(:,j)

          !m2f: Mp(:,iter) = Mp(:,iter) -Mp(:,j)'* Mp(:,iter) * Mp(:,j)
                Mp(:,iter) = Mp(:,iter) -Mp(j,:) * Mp(:,iter) * Mp(:,j)
            end do
            !norm(Mp(:,iter))

            !Normalize search direction
            p(:,iter)  =  p(:,iter) / (norm2(Mp(:,iter)))
            Mp(:,iter) = Mp(:,iter) / (norm2(Mp(:,iter)))


            !Update solution and residual
            alpha2 = r * Mp(:,iter) / (Mp(iter,:)) * (Mp(:,iter)))

            x = x + alpha2 * p(:,iter)
            r = r - alpha2 * Mp(:,iter)      ! where is the *(Cnew - C)?


            !Check convergence
!!!!        normr=norm2(r)                               !!!! norm
            !fprintf('norm(r) = !g iter = !gNewLine',normr,iter+1);
            if (normr < tol) then
                !fprintf('GCR Converged, iter = !gNewLine',iter+1);
                converged=1
                exit
            end if


        END DO !for loop

        if (normr > tol) then
            write(*,*) 'GCR SOLUTION DID NOT CONVERGE!'
            converged=0
        end if

        RETURN
    END subroutine gcr_Mfree

我正在单独编译子程序以解决所有问题。我解决了其他错误，但我无法解决这个问题。

gfortran -Wall -c "gcr_Mfree.f95" (in directory: /home/vahid/Dropbox/To    Move folder/Geany)
gcr_Mfree.f95:85.34:
            alpha2 = r * Mp(:,iter) / (Mp(iter,:)) * (Mp(:,iter)))
                              1
Error: Invalid character in name at (1)
Compilation failed.

另一方面，我想知道，如何验证数组元素和形状？特别是我在DO循环中使用（：，iter）的地方。我的意思是，数组在每次迭代时都会将形式向量转换为矩阵，并且矩阵的大小在每次迭代时都会变大。我知道我可以在编译后在显示器上打印它。我想知道数组的形状/元素，以确保我的方向正确。

Answer 1

正如casey评论的那样，这解决了你的问题，你的代码因为额外的右括号而出错。不过，说一件事作为答案可能会有所帮助。

你从gfortran得到的错误信息作为诊断信息似乎毫无帮助。查看代码的简化版本（没有完整的声明等）

  real, dimension(10,10) :: Mp
  alpha2 = r * Mp(:,iter) / (Mp(iter,:)) * (Mp(:,iter)))
end

并编译。使用gfortran 4.9，我收到了类似的消息：

alpha2 = r * Mp(:,iter) / (Mp(iter,:)) * (Mp(:,iter)))
                  1
Error: Invalid character in name at (1)

相反，使用ifort我得到了更多有用的

  error #5276: Unbalanced parentheses
  alpha2 = r * Mp(:,iter) / (Mp(iter,:)) * (Mp(:,iter)))
-------------------------------------------------------^

fortran中的编译错误：名称中的字符无效（1）

1 个答案: