中文说明：模型降阶的若干方法，用matlab编的，包括arnoldi_MIMO方法，Lanczos方法，mod_lanczos方法，OnesidedArnoldiV方法和svd_method方法
English Description：
Some methods of model reduction, including arnoldi_MIMO method, Lanczos method, method, mod_lanczos method, OnesidedArnoldiV method, matlab method and svd_method method, are used to reduce the order of the model.