用快速排序方法时出现的问题

学客 · 发表于 2018-3-7 12:49:54

module qsort_c_module
   implicit none
   public :: QsortC
   private :: Partition
   contains
   recursive subroutine QsortC(A,B)
   real, intent(in out), dimension(:) :: A
   real, intent(in out), dimension(:,:) :: B
   integer :: iq
   if(size(A) > 1) then
   call Partition(A, iq, B)
   call QsortC(A(:iq-1),B(:,:iq-1))
   call QsortC(A(iq:),B(:,iq:))
   endif
   end subroutine QsortC
   subroutine Partition(A, marker, B)
   real, intent(in out), dimension(:) :: A
   real, intent(in out), dimension(:,:) :: B
   integer, intent(out) :: marker
   integer :: i, j
   real :: temp
   real ,dimension(1:size(A))::temb
   real :: x    ! pivot poin
   x = A(1)
   i= 0
   j= size(A) + 1
   do
      j = j-1
   do
   if (A(j) <= x) exit
   j = j-1
   end do
   i = i+1
   do
      if (A(i) >= x) exit
      i = i+1
   end do
   if (i < j) then
      ! exchange A(i) and A(j)
      temp = A(i)
      temb = B(:,i)
      A(i) = A(j)
      B(:,i)=B(:,j)
      A(j) = temp
      B(:,j)=temb
   elseif (i == j) then
      marker = i+1
      return
   else
      marker = i
      return
   endif
   end do
   end subroutine Partition
   end module qsort_c_module
   program www_fcode_cn
   use qsort_c_module
   implicit none
   integer, parameter :: r = 3
   real, dimension(1:r) :: myarray = (/0, 50, 20/)
   real, dimension(1:r,1:r) :: mb=(/1,2,3,4,5,6,7,8,9/)
   write(2,*) "原数组:", myarray
   write(2,'*') "原数组:", mb
   call QsortC(myarray,mb)
   write(2,*) "排序后:", myarray
   write(2,'*') "排序后:", mb
   end program www_fcode_cn

用这个修改后的快速排序法，排列特征值A，和特征向量B，出现了错误：
B排序输出后，出现了这样的数字：1.000000    2.000000    3.000000    7.000000
8.000000    9.000000    4.000000    5.000000    -1.5823616E-26
请问是哪里出错了，非常感谢