如何在OMPython中设置模型仿真输出文件的存储目录？

使用OMPython的ModelicaSystem对象运行模型时，仿真输出文件默认会存到用户目录，无法方便地批量清理。想要自定义这些文件的存储目录（推测为工作目录），但两次尝试均未解决问题：

第一次尝试（未生效） #

直接修改ModelicaSystem的currDir属性无法生效：

from OMPython import OMCSessionZMQ
omc = OMCSessionZMQ()
model_path=omc.sendExpression("getInstallationDirectoryPath()") + "/share/doc/omc/testmodels/"
simulation_path=omc.sendExpression("getTempDirectoryPath()")+"OMtmp/"

from OMPython import ModelicaSystem
mod=ModelicaSystem(model_path+"BouncingBall.mo","BouncingBall")
mod.currDir=simulation_path
mod.simulate()

第二次尝试（无法删除临时目录） #

通过os.chdir()切换Python工作目录后，OMC会话未同步目录变化，且仿真文件被进程占用无法删除：

import os
import errno
import shutil

from OMPython import OMCSessionZMQ
from OMPython import ModelicaSystem

omc = OMCSessionZMQ()

# Create temporary directory
simulation_path=omc.sendExpression("getTempDirectoryPath()")+"OMtmp/"
home_path=os.getcwd()
try:
    os.mkdir(simulation_path)
except OSError as e:
    if e.errno != errno.EEXIST:
        raise
os.chdir(simulation_path)
print("Working directory->"+os.getcwd())

# Loading the model and simulating
model_path=omc.sendExpression("getInstallationDirectoryPath()") + "/share/doc/omc/testmodels/"
mod=ModelicaSystem(model_path+"BouncingBall.mo","BouncingBall")
mod.simulate()
res=mod.getSolutions(["time","h"])
print("The heigth is "+str(res[1,-1])+" m")

#Changing the working directory to the original one
os.chdir(home_path) 
# We could delete files and dierctory using: shutil.rmtree(simulation_path)
# But don't work. Plan b, delete al de files in the directory
for files in os.listdir(simulation_path):
    path = os.path.join(simulation_path, files) 
    try:
        shutil.rmtree(path)
    except OSError:
        os.remove(path)
# Still don't work: os.rmdir(simulation_path)

正确解决方案 #

要指定仿真输出目录，需通过OMC会话的cd()命令切换工作目录，同时确保仿真完成后释放文件锁：

import os
import shutil
from OMPython import OMCSessionZMQ, ModelicaSystem

# 创建OMC会话
omc = OMCSessionZMQ()

# 设置路径
model_path = omc.sendExpression("getInstallationDirectoryPath()") + "/share/doc/omc/testmodels/"
simulation_path = omc.sendExpression("getTempDirectoryPath()") + "OMtmp/"

# 确保仿真目录存在
os.makedirs(simulation_path, exist_ok=True)

# 让OMC会话切换到目标目录
omc.sendExpression(f'cd("{simulation_path}")')

# 加载模型并仿真
mod = ModelicaSystem(model_path + "BouncingBall.mo", "BouncingBall")
mod.simulate()

# 获取结果
res = mod.getSolutions(["time", "h"])
print(f"The height is {res[1,-1]} m")

# 关闭OMC会话，释放文件锁
omc.sendExpression("quit()")

# 删除仿真目录及所有文件
shutil.rmtree(simulation_path)

关键要点 #

• 必须通过omc.sendExpression(f'cd("{simulation_path}")')让OMC内核切换工作目录，才能让仿真输出文件生成在指定路径
• 仿真完成后调用omc.sendExpression("quit()")关闭OMC会话，避免文件被进程占用无法删除
• 使用os.makedirs(..., exist_ok=True)简化目录创建逻辑，无需手动处理已存在的情况

内容的提问来源于stack exchange，提问作者Alberto