Knot optimization and accurate calculation for error of fitvalue.
结点的优化；拟合值误差的严格计算。
2
If you do not specify a value, DB2 determines a best fitvalue and USES that value.
如果不指定一个值，DB 2自行决定一个最适合的值，并使用那个值。
3
The valuefit matters, says Cialdini, because innovation is, in part, a process of change, and under that pressure we, as a species, behave differently.