我有一个.mat文件中的实验数据和一个用dymola编写的模型 . 我使用dymolaM.m文件将命令从matlab发送到dymola . 通过这种方式，我可以使用matlab来优化我的模型的参数 . Matlab从.mat文件中读取数据，以正确的方式初始化dymola，让dymola模拟模型，读取dymola的输出并将其与实验数据进行比较 .

这一切都适用于诡计，但如果我重复matlab dymola连接太多我总是得到以下错误：

??? Error using ==> ddeexec

The first argument 'channel' is not valid.

Error in ==> dymolaM at 59

status = ddeexec(DymolaChannel, deblank(command(i,:)), '', timeout);

我尝试重复完全相同的命令200次 . 我总是在迭代26得到错误 .

我该怎么办？这是dymolaM.m文件的代码

function res=dymolaM(command, value)

% Executes a command optionally followed by a value in Dymola.

% Dymola is started if not already running.

% Version 1.0, 1997-11-14

% Version 1.1, 1999-06-12

% Copyright (C) 1997-2001 Dynasim AB.

% All rights reserved.

DymolaChannel = ddeinit('dymola', ' ');

if DymolaChannel == 0,

pause(1);

DymolaChannel = ddeinit('dymola', ' ');

if DymolaChannel == 0,

dymola = getenv('DYMOLA');

v=version;

if (isempty(dymola) & v(1,1)>='5')

if v(1,1)>='7'

[st,I]=dbstack('-completenames');

else

[st,I]=dbstack;

end

if v(1,1)>='7'

currentfile=st(I).file;

else

currentfile=st(I).name;

end

I=find(currentfile=='\' | currentfile=='/');

currentfile=currentfile(1:(max([1,I(1:end-1)])-1));

dymola=currentfile;

end

if ~isempty(dymola)

dymola=[dymola,'\bin\'];

end

disp('Starting Dymola - Wait');

fquote = '';

if strcmp(computer, 'PCWIN') | strcmp(computer, 'PCWIN64')

fquote = '"';

end;

dos([fquote,dymola,'Dymola',fquote,' &']);

pause(10);

DymolaChannel = ddeinit('dymola', ' ');

disp('Dymola started');

else

disp('Worked around problem communicating with Dymola');

end

end

if nargout>0

res=zeros(size(command,1),1);

end

if DymolaChannel == 0,

disp('Error starting Dymola');

elseif nargin > 0,

for i=1:size(command,1)

timeout=4000*1000; % Can always kill dymola

if nargin == 1,

status = ddeexec(DymolaChannel, deblank(command(i,:)), '', timeout);

elseif nargin == 2,

status = ddeexec(DymolaChannel, [deblank(command(i,:)), num2str(value(i))], '', timeout);

end

if nargout==0

if status == 0,

error('Invalid Dymola command.');

end

else

res(i)=status;

end;

end

ddeterm(DymolaChannel);

end