Fortran - 重塑函数

下表描述了重塑功能：

功能 描述
重塑（源、形状、焊盘、顺序） 它从给定数组源中的元素开始构造一个具有指定形状 shape 的数组。如果不包括焊盘，则源的尺寸必须至少为产品（形状）。如果包含 pad，则它必须与源具有相同的类型。如果包含 order ，则它必须是与 shape 具有相同形状的整数数组，并且值必须是 (1,2,3,...,n) 的排列，其中 n 是 shape 中的元素数量，它必须小于或等于 7。

例子

下面的例子演示了这个概念：

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

当上面的代码被编译并执行时，会产生以下结果：

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
fortran_arrays.htm