大家看这是什么问题？我花好长时间都没解决
 

Warning: The model 'untit' does not have continuous states, hence using the solver 'VariableStepDiscrete' instead of solver 'ode45'. You can disable this diagnostic by explicitly specifying a discrete solver in the solver tab of the Configuration Parameters dialog, or setting 'Automatic solver parameter selection' diagnostic to 'none' in the Diagnostics tab of the Configuration Parameters dialog.

如何产生的
 

这是我在设计FIR滤波器时，将其模型进行signalcompiler产生的问题