用来计算曲线包络线的小程序，通过该程序可以线性包络显示某一程序所生成的曲线在该包络线范围内的变化情况。一般在数值计算方面应用较多。-Small program used to calculate the curve envelope the linear envelope curve generated by a program through the program can vary within the scope of this envelope. Generally used more