matlab - 如何在不查看显示的警告的情况下意识到 ode45 的故障？

Question

当ODE45的解发散时(不管为什么发散，如何发散)，会出现如下警告，求解器无法继续:

Warning: Failure at t=8.190397e+01. Unable to meet integration tolerances without reducing the step size below the smallest value allowed (2.273737e-13) at time t.

我在矩阵(大量输入)上运行 ode45，所以我想自动找出发生上述情况(失败)的输入。我的意思是，ode45 返回的这种情况是否有任何其他迹象可以自动写入数组？可以在 if 语句中使用的东西:

如果{返回某个变量/等于...}，则{求解器失败}

自动识别那些错误的输入，而无需查找显示的警告。

Answer 1

您可以将那个警告变成一个错误，错误可以被try/catch block 捕获.

一个例子:

% Change this particular warning into an error
warnId = 'MATLAB:ode45:IntegrationTolNotMet';
warnstate = warning('error', warnId);    

% That can be caught with try/catch
try     
    % Quick-failing integration, suggested by horchler
    [t,y] = ode45(@(t,y)[y(1)^2;y(2)],[0 1],[1;1]);

catch ME
    % Check if we indeed failed on meeting the tolerances
    if strcmp(ME.identifier, warnId)

        % DO YOUR STUFF HERE

    else
        % Something else has gone wrong: just re-throw the error
        throw(ME);
    end

end

% Don't forget to reset the warning status
warning(warnstate);

您可以通过lastwarn 命令获取任何警告的warnId。有关错误，请参阅 lasterr。