如何将一个巨大的矩阵逐行写入文件(fortran 90) [英] how to write a huge matrix to file row by row (fortran 90)

问题描述

我想将包含大量数据的矩阵逐行写入文件.例如，我有一个 100*100 的矩阵，我想在文件中以 100*100 的形式拥有它.但是，它不起作用.以下是我的代码和一些描述.N 和 M 是大约数百个整数.RECL 是我设置文件的预期长度，但这里似乎这个命令不起作用.当 N 设置为 99 时，输出为 198 行M 设置为 200. Vec 是双精度复数矩阵.如何输出 Vec 的值并保持其原始格式 N*M?我的编译命令是ifort -o out test.f90".

I want to write a matrix with a lot of data to a file row by row. For example, I have a matrix 100*100 and I want to have it in form 100*100 in the file. However, it doesn't work.Following is my code and some description. N and M are integers around some hundreds. RECL is expected length I set the file but here it seems this command does not work. The output is with 198 lines when N is set 99 and M is set 200. Vec is a double precision complex matrix. How could I output the values of Vec keeping its original format N*M? My compile command is "ifort -o out test.f90".

open(unit=2, file='graph1.txt', ACTION="write", STATUS="replace",RECL=40*M+10)
do i=1,N
 do j=1,M
  write(2, '(F)', advance='no') real(Vec(i,j)) 
 end do
  write(2, *) '' 
end do

按照@george 的建议，我编写了这样的程序:

Following @george advice, I coded a program like this:

program test
implicit none

integer i,j

open(unit=2, file='graph1.txt', ACTION="write", STATUS="replace")
do i=1,500
 write(2, '(1600F14.7)')( 0.00001 ,j=1,499)
end do

close(2)

end

有了这段代码，问题就解决了！可能我上次没有正确编译.

With this code, problem solved! Maybe I didn't compile correctly last time.

推荐答案

扩展我的评论，您还应该使用隐式循环..试试这个:

expanding on my comment, you should also use an implicit loop..try this:

open(unit=2, file='graph1.txt', ACTION="write", STATUS="replace")
do i=1,N
     write(2, '(1000F14.7)')( real(Vec(i,j)) ,j=1,M)
end do

或者对于足够现代的编译器(我不确定有多新……)

or for sufficiently modern compilers (I'm not sure how new.. )

     write(2, '(*(F14.7))')( real(Vec(i,j)) ,j=1,M)

请注意，如前所述，(F14.7) 周围的括号对于 2008 标准中的 * unlimited-format-item 是必需的.

Note as has been pointed out, the parenthesis around (F14.7) are required for the * unlimited-format-item in the 2008 standard.

也可以拉入其他评论，你也可以这样做:

may as well pull in the other comments, you can also do this:

      write(2, '(*(F14.7))')real(Vec(i,:M))

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