固定步ODE4求解器中的S函数

Question

我做了一个简单的s函数，可以通过检查输入端口是否为NaN类型来抛出异常：

s-function块用于具有固定步长ODE4求解器的Simulink模型。但是，在运行此模型时，我收到以下警告：The model 'testError' does not have continuous states, hence Simulink is using the solver 'FixedStepDiscrete' instead of solver 'ode4'.。我应该在mdlInitializeSizes或mdlInitializeSampleTimes函数中更改什么才能确保s函数与OD4求解器一起运行？

static void mdlInitializeSizes(SimStruct *S)
{
    ssSetNumSFcnParams(S, 0);
    if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S)) {
        return; /* Parameter mismatch will be reported by Simulink */
    }

    if (!ssSetNumInputPorts(S, 1)) return;
    ssSetInputPortWidth(S, 0, 1);
    ssSetInputPortDataType(S, 0, SS_DOUBLE);
    ssSetInputPortDirectFeedThrough(S, 0, 1);

    /* specify the sim state compliance to be same as a built-in block */
    //ssSetSimStateCompliance(S, HAS_NO_SIM_STATE);

    ssSetOptions(S,
                 SS_OPTION_DISALLOW_CONSTANT_SAMPLE_TIME |
                 SS_OPTION_WORKS_WITH_CODE_REUSE |
                 SS_OPTION_USE_TLC_WITH_ACCELERATOR);
}

static void mdlInitializeSampleTimes(SimStruct *S)
{
    /*
     * the first sample time, continuous
     */
    ssSetSampleTime(S, 0, INHERITED_SAMPLE_TIME);
    ssSetOffsetTime(S, 0, 0);
    ssSetModelReferenceSampleTimeDefaultInheritance(S); 
}