等值线

在科学计算和现实生活中，常常会遇到y=f(t)这类函数关系，例如，正弦、余弦等等。函数y=f(t)往往是以离散的观测值形式f(ti)(i=1,....N)表现出来的。例如，令股民朋友如醉如痴的K线图，与千家万户性命攸关的河流水位曲线图等等。离散函数关系有不少数据处理课题，例如，数据拟合、插值和平滑等等。最令人兴奋的还是预测，如果股民朋友能够准确把握y=f(t)的走向，钞票就会源源不断涌入口袋。如果水文学家能够准确预测河流水位暴涨的过程，可以大量减少生命和财产损失。

所谓画曲线就是描绘y=f(t)的图象，在本书我们将通过图象绘制直观地了解观测值的变化和数据处理方法的效果-contours in scientific computing and real-life, we will often encounter y = f (t) such a function, such as sine, cosine and so on. Function y = f (t) tend to be discrete observation form f (t) (i = 1 ...... N) the performance. For example, investors simply friends of K map, and the millions of lives at stake curve of water levels in rivers and so on. Discrete function of a number of data-processing tasks, such as data fitting, interpolation and smoothing and so on. Most exciting is predicted that if shareholders friends to accurately grasp y = f (t) trend, money will continue to flood into pockets. If hydrologists can accurately predict river levels rose process, a significant reduction in loss of life and property. The so-called curve is painting depicting y = f (t) of the image, in this