In this paper two reasons-the deviation of the data from the origin and the size of the data-causing the ill-conditioned normal equations in the least square fitting of a polynomial are discussed.

讨论了最小二乘多项式拟合中引起正规方程组病态的两个重要原因：节点对原点的偏离程度和节点坐标的数量级。

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The ionization of one dimensional model atoms in ultra intense laser fields has been studied by solving time dependent Schrdinger equation using the least square fitting and the Runge Kutta methods.

利用最小二乘法和龙格库塔方法求解含时薛定谔方程，研究了一维原子模型在超强激光场中的电离。

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Substantially, this method is a smoothing process resulted from the mathematical skills of weighted least square fitting, combining with the iterative method for correct indexing.

其方法实质上是加权最小二乘拟合与叠代修正指标化的技巧相结合的平滑过程。

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