Fortran - 重塑函数

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  简述

  下表描述了重塑功能：

  功能	描述
  reshape(source, shape, pad, order)	它从给定数组源中的元素构造一个具有指定形状形状的数组。如果不包括焊盘，则源的大小必须至少是产品（形状）。如果包含 pad，它必须与 source 具有相同的类型。如果包含 order，它必须是一个与 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，它必须小于或等于 7。

  Example

  以下示例演示了该概念：

  
  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，它会产生以下结果：

  
  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