fortran - Fortran 函数重塑的问题

Question

我正在使用代码块和 gnu 编译器来运行 Fortran 代码，但我注意到一些非常奇怪的东西。一旦我有一个数组(1,2,3,...,16)，如果我想重塑为一个 4x4 矩阵，我会使用内置reshape函数，理论上它应该对数字使用列优先顺序，因此给出(1 5 9 13; 2 6 10 14; 3 7 11 15; 4 8 12 16); 相反，我得到(1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16). 这是一个主要的不一致，我想知道它是否与使用代码块或什么有关。任何其他有此问题和/或有关原因和解决方案的想法的人。

标签： fortrancodeblocksreshape

Answer 1

我无法复制这个问题Intel Fortran oneAPI HPC

和参考代码

program FortranConsole1
use, intrinsic :: iso_fortran_env
implicit none

interface show
    procedure show_matrix_i, show_matrix_r, show_matrix_d
end interface

integer :: row(16), matrix(4,4)
real(real64) :: A(4,4)

row = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]    
matrix = reshape( row, [4, 4])
       
call show(matrix)

A = dble(matrix)

A = sqrt( matmul( transpose(A), A) )

call show(A, 8)
call show(A, 12)
call show(A, 16)

contains

subroutine show_matrix_i(A, w)
! Display the matrix 'A' in columns
!   A : the array of integers
!   w : the column width. Default = 5
    integer, intent(in) :: A(:,:)
    integer, intent(in), optional :: w
    integer :: i,j,n,m, wt
    character(len=16) :: fmt
    if(present(w)) then
        wt = w
    else
        wt = 5
    end if
    n = size(A,1)
    m = size(A,2)
    write( fmt, "(a,g0,a)") "(*(g",wt,".0))"        
    write( * , fmt ) ( (A(i,j),j=1,m), new_line("A"), i=1,n )
end subroutine

subroutine show_matrix_r(A, w)
! Display the matrix 'A' in columns
!   A : the array of real numbers
!   w : the column width. deafult = 12
!   s : sig. figures w-5 (calculated)
    real(real32), intent(in) :: A(:,:)
    integer, intent(in), optional :: w
    integer :: i,j,n,m,dg,wt
    character(len=16) :: fmt
    if(present(w)) then
        wt = w
    else
        wt = 12
    end if
    dg = wt-5
    n = size(A,1)
    m = size(A,2)
    write( fmt, "(a,g0,a,g0,a)") "(*(g",wt,".",dg,"))"
    write( * , fmt ) ( (A(i,j),j=1,m), new_line("A"), i=1,n )
end subroutine

subroutine show_matrix_d(A,w)
! Display the matrix 'A' in columns
!   A : the array of dble numbers
!   w : the column width. default = 12
! Converts 'A' into single precision and calls `show_matrix_r`
    real(real64), intent(in) :: A(:,:)
    integer, intent(in), optional :: w
    call show_matrix_r(real(A),w)
end subroutine

end program FortranConsole1

结果