复化三点Gauss-lengend公式求pi，用于特征降维，特征融合，相关分析等,包括单边带、双边带、载波抑制及四倍频。- Complex of three-point Gauss-lengend the Formula pi, For feature reduction, feature fusion, correlation analysis, Including single sideband, double sideband, suppressed carrier and quadruple.