皮尔逊-Ⅲ型分布曲线的快速通用算法研究

Study of the Rapid and Universal Arithmetic of P-Ⅲ Distribution Curve

在编制城市暴雨强度公式时 ,频率分布曲线常采用皮尔逊 -Ⅲ型分布曲线 ,而该曲线的快速通用算法一直是难点问题。目前 ,在实际工作中应用的各种算法都有一定的缺陷性 ,因此 ,为皮尔逊 -Ⅲ型分布在编制暴雨强度公式中的应用带来困难。为此 ,通过数学表达式的变换 ,将皮尔逊 -Ⅲ型分布转换为不完全Г函数 ,并给出其快速通用的算法模型。通过算法对比和实践验证 ,该模型具有算法简单、求解灵活、通用性强、收敛速度较快、计算精度较高等优点 。

The rapid and universal arithmetic of P-Ⅲ distribution curve which is used as frequency distribution curve in compiling urban rainstorm intensity formula is a hard work. At present, there are diversified arithmetics in practice and they all have some limitations. This added difficulty to application of P-Ⅲ distribution curve. In this paper, P-Ⅲ distribution curve has been transformed into incomplete Γ function and the model of P-Ⅲ distribution curve is got by transformation of the mathematical expression. The result of comparing arithmetic and testing shows that this model has simple and flexible arithmetic, good universality and convergence. It can be generally applied.