Fortran - Reshape 函数
下表描述了 reshape 函数:
| 函数 | 描述 |
|---|---|
| reshape(source, shape, pad, order) | 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 pad，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。 |
示例
以下示例演示了这个概念:
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
