如何使用子进程模块从python脚本运行AVL（二进制）？

Question

I'm trying to script a series of runs in AVL (Athena Vortex Lattice) , a vortex lattice code for designing wings and other lifting surfaces.

I have the binary stored in ~/bin/. Typically you run AVL within a terminal, and enter commands. Typical commands would be:

1. LOAD ~/path/avlexamplefile.avl
2. OPER
3. AA 5
4. X
5. FS
6. RETURN
7. QUIT

Which, loads a .avl input file, enter the operations menu, sets the angle of attack to 5 degrees, executes the computation, Prints out the forces to an output file, exits the operations menu, and quits the program.

I'm trying to run AVL from a python script using the subprocess module using the following code:

    import subprocess as sp
    avl = sp.Popen(['~/bin/avl3.35'],
           stdin=sp.PIPE,stdout=None, 
           stderr=None, 
           universal_newlines=True)

    avl.communicate('LOAD ~/file/avlexamplefile.avl')

This almost works. AVL loads, the first command is executed, but then I get the following error, and won't take any further commands.

    AVL   c>  forrtl: severe (24): end-of-file during read, unit -4, file        stdin
    Image              PC                Routine            Line        Source             
    avl3.35            000000010A00F43B  Unknown               Unknown  Unknown
    avl3.35            000000010A00DBFE  Unknown               Unknown  Unknown
    avl3.35            0000000109FD5177  Unknown               Unknown  Unknown
    avl3.35            0000000109F8B426  Unknown               Unknown  Unknown
    avl3.35            0000000109F8AA39  Unknown               Unknown  Unknown
    avl3.35            0000000109FB61F3  Unknown               Unknown  Unknown
    avl3.35            0000000109EEECF3  Unknown               Unknown  Unknown
    avl3.35            0000000109E7130F  Unknown               Unknown  Unknown
    avl3.35            0000000109E6FC7C  Unknown               Unknown  Unknown
    libdyld.dylib      00007FFF8B1D95AD  Unknown               Unknown  Unknown

Can anyone point out what I'm doing wrong? Eventually, I'd like to place the above inside a for loop for running through multiple variations.

Answer 1

Try using avl.stdin.write("your cmd here" +'\\n') .

Working example using xfoil is here (not mine):

https://github.com/Launchpad-McQ/Aileron-design/blob/master/design-aileron.py