This paper describes the general principle, calculus for thin film comparative method of cryoscopy,and concerned problems in the measure.

By studying the point-to-point comparison method,the author presented a new algorithm based on point-to-point comparison method.

The paper discussed the principle of traditional point-to-point comparison method of linear interpolation, and brought forward two different improved algorithms, which principles were also discoursed upon.

Algorithm for linear interpolation of four coordinates with point-by-point comparison method;

Based on the long-time practice and the rich experience in teaching numerical control technology and upon comparison, analysis and study, the paper points out that the interpolation operation of the spatial beeline can be realized by point-by-point comparison so as to realize the three axes linkage control.

The diagonal ellipse arc interpolation based upon Point by Point comparison method;

The elemental principles of point by point comparison method and the improvement of circular interpolation were introduced, as well as the implementation algorithm with the advanced computer language after improvement.

There are many advantages to adapt polar coordinates system interpolation in swing structural machines,In this paper,by using point by point comparison method to achieve line interpolation and circle interpolation control algorithms in polar coordinates,and introduced the distribution of error in polar coordinates.