提供了一种三参gamma分布定参的程序（程序中离散单位长度为1），R^2是统计量相关系数考虑了未知量的个数(2个)和拟合的精度。-Providing the program (in discrete units of length 1) A three-parameter gamma distribution given ginseng, R ^ 2 is the statistical correlation coefficient takes into account the amount