北巷的猫

Lagrange插值原理：li(x)=(x−x0)…(x−xi−1)(x−xi+1)…(x−xn)(xi−x0)…(xi−xi−1)(xi−xi+1)…(xi−xn)l_{i}(x)=\frac{(x-x_{0})\dots(x-x_{i-1})(x-x_{i+1})\dots(x-x_n)}{(x_i-x_0)\dots(x_i-x_{i-1})(x_i-x_{i+1})\dots(x_...

A = randi([-5,5],4,4) %生成从-5到5，大小为4×4的随机矩阵A = 3 1 5 5 4 -4 5 0 -4 -2 -4 3 5 1 5 -4diag(A) %取一个矩阵的对角元素ans = 3 -4 -4 -...

MATLAB中有自带的三次样条插值函数插值函数:spline,调用方法： yk =spline(x,y,xk)例子：% 读取插值数据a = load('data.txt');x = a(:,1);y = a(:,2);xx = linspace(max(x),min(x),100);yy = spline(x,y,xx); %三次样条插值% 保存插值结果fileID...

插值函数:interp1,调用方法： yk =interp1(x,y,xk,‘method’)注意：interp1的最后一个是数字 '1 ‘，不是字母’ l ’例子：% 读取数据a = load('data.txt');x = a(:,1)y = a(:,2)xi = linspace(min(x),max(x),100);% 插值yl = interp1(x,y,xi,'...

MATLAB/octavex = -8:0.5:8;y = x;[X,Y] = meshgrid(x,y);R = sqrt(X.^2+Y.^2)+eps;Z = sin(R)./R;mesh(X,Y,Z);grid onaxis([-10 10 -10 10 -1 1])Xlabel('x')Ylabel('Y')Zlabel('Z')pythonimport nu...