Fortran-関数の変形

次の表で、reshape関数について説明します。

Function

Description

reshape(source, shape, pad, order)

It constructs an array with a specified shape shape starting from the elements in a given array source. If pad is not included then the size of source has to be at least product (shape). If pad is included, it has to have the same type as source. If order is included, it has to be an integer array with the same shape as shape and the values must be a permutation of (1,2,3,…,n), where n is the number of elements in shape , it has to be less than, or equal to 7.

例

次の例は、概念を示しています。

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

上記のコードをコンパイルして実行すると、次の結果が生成されます。

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-reshape

Fortran-関数の変形