s-function中怎么把状态以及输出都定义成元胞数组，举一个例子

在S-Function中，状态和输出可以定义为元胞数组。下面是一个简单的例子：

function [sys,x0,str,ts,simStateCompliance] = mySfunc(t,x,u,flag)

switch flag
    case 0 % Initialization
        sizes = simsizes;
        sizes.NumContStates = 0;
        sizes.NumDiscStates = 2;
        sizes.NumOutputs = 2;
        sizes.NumInputs = 1;
        sizes.DirFeedthrough = 1;
        sizes.NumSampleTimes = 1;
        sys = simsizes(sizes);
        x0 = {0, 0}; % Initialize the states as a cell array
        str = [];
        ts = [0 0]; % Continuous sample time = 0, discrete sample time = [0 0]
        simStateCompliance = 'DefaultSimState';
        
    case 2 % Discrete states update
        x1 = x{1}; % Extract the first state
        x2 = x{2}; % Extract the second state
        y = u; % Output is the input signal
        sys = {x1 + y, x2 - y}; % Update the states as a cell array
        
    case 3 % Outputs
        x1 = x{1}; % Extract the first state
        x2 = x{2}; % Extract the second state
        y1 = x1; % First output is the first state
        y2 = x2; % Second output is the second state
        sys = {y1, y2}; % Return the outputs as a cell array
        
    case {1, 4, 9} % Unused flags
        sys = [];
        
    otherwise
        error(['Unhandled flag = ',num2str(flag)]);
end

在这个例子中，我们定义了两个离散状态和两个输出，它们都是元胞数组。在离散状态更新（flag=2）和输出（flag=3）中，我们可以使用花括号语法来提取和更新状态和输出。在这个例子中，我们使用了单独的变量来存储状态和输出，但是也可以直接使用元胞数组来存储它们。