Fortran - 重塑函式

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下表描述了 reshape 函式

函式 描述
reshape(源，形狀，填充，順序) 它利用給定陣列源中的元素構建一個指定形狀形狀的陣列。如果未包含填充，則源的大小必須至少為乘積(形狀)。如果包含填充，它必須與源具有相同的型別。如果包含順序，則它必須是具有與形狀相同的形狀的整數陣列，並且其值必須是(1,2,3,...,n)的排列，其中 n 是形狀中元素的數量，它必須小於或等於 7。

示例

以下示例演示了該概念

program arrayReshape
implicit none

interface
   subroutine write_matrix(a)
   real, dimension(:,:) :: a
   end subroutine write_matrix
   end interface

   real, dimension (1:9) :: b = (/ 21, 22, 23, 24, 25, 26, 27, 28, 29 /)
   real, dimension (1:3, 1:3) :: c, d, e
   real, dimension (1:4, 1:4) :: f, g, h

   integer, dimension (1:2) :: order1 = (/ 1, 2 /)
   integer, dimension (1:2) :: order2 = (/ 2, 1 /)
   real, dimension (1:16) :: pad1 = (/ -1, -2, -3, -4, -5, -6, -7, -8, &
                                 & -9, -10, -11, -12, -13, -14, -15, -16 /)

   c = reshape( b, (/ 3, 3 /) )
   call write_matrix(c)

   d = reshape( b, (/ 3, 3 /), order = order1)
   call write_matrix(d)

   e = reshape( b, (/ 3, 3 /), order = order2)
   call write_matrix(e)

   f = reshape( b, (/ 4, 4 /), pad = pad1)
   call write_matrix(f)

   g = reshape( b, (/ 4, 4 /), pad = pad1, order = order1)
   call write_matrix(g)

   h = reshape( b, (/ 4, 4 /), pad = pad1, order = order2)
   call write_matrix(h)

end program arrayReshape


subroutine write_matrix(a)
   real, dimension(:,:) :: a
   write(*,*)
   
   do i = lbound(a,1), ubound(a,1)
      write(*,*) (a(i,j), j = lbound(a,2), ubound(a,2))
   end do
end subroutine write_matrix

編譯並執行以上程式碼後，它將生成以下結果

21.0000000  24.0000000  27.0000000    
22.0000000  25.0000000  28.0000000    
23.0000000  26.0000000  29.0000000    

21.0000000  24.0000000  27.0000000    
22.0000000  25.0000000  28.0000000    
23.0000000  26.0000000  29.0000000    

21.0000000  22.0000000  23.0000000    
24.0000000  25.0000000  26.0000000    
27.0000000  28.0000000  29.0000000    

21.0000000  25.0000000  29.0000000   -4.00000000    
22.0000000  26.0000000  -1.00000000  -5.00000000    
23.0000000  27.0000000  -2.00000000  -6.00000000    
24.0000000  28.0000000  -3.00000000  -7.00000000    

21.0000000  25.0000000  29.0000000   -4.00000000    
22.0000000  26.0000000  -1.00000000  -5.00000000    
23.0000000  27.0000000  -2.00000000  -6.00000000    
24.0000000  28.0000000  -3.00000000  -7.00000000    

21.0000000  22.0000000  23.0000000   24.0000000    
25.0000000  26.0000000  27.0000000   28.0000000    
29.0000000  -1.00000000 -2.00000000  -3.00000000    
-4.00000000 -5.00000000 -6.00000000  -7.00000000
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