如何将 Piecewise[] 与可变数量的图形/间隔一起使用 [英] How can I use Piecewise[] with a variable number of graphs/intervals

问题描述

我正在编写一个程序来进行三次样条插值.基本上，该程序将在某些间隔内拼凑三次多项式.如果可能的话，我想用piecewise[] 或其他类似函数绘制这个结果.

I'm writing a program to do cubic spline interpolation. Basically the program will piece together cubic polynomials over certain intervals. I would like to graph this result if all possible with piecewise[] or another similar function.

在我的代码中，我的方程在一个数组中，输出如下(例如):

In my code I have my equations in an array that outputs like this (for example):

{2+3/4 (-1+X$6836)+1/4 (-1+X$6836)^3,3+3/2 (-2+X$6836)+3/4 (-2+X$6836)^2-1/4 (-2+X$6836)^3}

我还有另一个数组，用于分别存储上面每个方程的特定间隔:

I also have another array that stores the specific intervals to graph over for each equation above, respectively:

{{1<=X$6836<=2},{2<=X$6836<=3}}

两个数组中方程的数量可以是可变的，所以我需要能够在分段[]中考虑到这一点.

The number of equations in both arrays can be variable so I need to be able to account for this in piecewise[].

推荐答案

为了确保我理解你，你的意思是这样的?

Just to make sure I understand you, you mean something like this?

eq = {2 + 3/4 (-1 + x) + 1/4 (-1 + x)^3, 
   3 + 3/2 (-2 + x) + 3/4 (-2 + x)^2 - 1/4 (-2 + x)^3};
cond = {{1 <= x <= 2}, {2 <= x <= 3}};
p = Piecewise[Thread[{eq, cond}]]

这篇关于如何将 Piecewise[] 与可变数量的图形/间隔一起使用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！