Difference Schemes Basing on Coefficient Approximation
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摘要: 对于变系数微分方程，在每个离散子区间上用函数去逼近系数比用一常数去代替系数,所得到的一系列近似微分方程有更高的精度．通常的差分格式建立在解函数在子区间上的Taylor展开式的近似的基础上,这样要求函数相对于网格是缓变的．而基于系数Taylor展开的近似式和局部基的引入,使得方法能在子区间上精确表达比二次函数丰富得多的解函数．由此构造的差分格式能在子区间上反映解具有迅速变化（如边界层，高振荡）的复杂的物理现象．数值实验（边值问题、特征值问题）显示了新方法比传统方法有更满意的效果．Abstract: In respect of variable coefficient differential equations,the equations of coefficient function approximation were more accurate than the coefficient to be frozen as a constant in every discrete subinterval.Usually,the difference schemes constructed based on Taylor expansion approximation of the solution don't suit the solution with sharp function.Introducing into local bases to be combined with coefficient function approximation,the difference can well depict more complex physical phenomena,for example,boundary layer as well as high oscillatory,with sharp behavior.The numerical test shows the method is more effective than the traditional one.
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Key words:
- boundary value problem /
- eigenvalue /
- coefficient approximation /
- local exact scheme
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