帮我用matlab写一个三次样条插值的程序，命题如下“给定数据x=0.25，0.30，0.39，0.45，0.53；y=0.5，0.5477，0.6245，0.6708，0.728；给定S（x）并满足条件S（x）'（0.25)=1,S''(0.53)=0.6868”

以下是一个可能的三次样条插值程序：

% 给定数据
x = [0.25, 0.30, 0.39, 0.45, 0.53];
y = [0.5, 0.5477, 0.6245, 0.6708, 0.728];

% 计算自然边界条件
n = length(x);
A = zeros(n, n);
b = zeros(n, 1);
A(1, 1) = 1;
A(n, n) = 1;
for i = 2:n-1
h1 = x(i) - x(i-1);
h2 = x(i+1) - x(i);
A(i, i-1:i+1) = [h1, 2*(h1+h2), h2];
b(i) = 3/h2*(y(i+1)-y(i))-3/h1*(y(i)-y(i-1));
end
c = A\b;

% 计算插值函数
syms t;
S = sym(zeros(1, n-1));
for i = 1:n-1
h = x(i+1) - x(i);
S(i) = (c(i)/(3*h))*(t-x(i))^3 + (c(i+1)/(3*h))*(x(i+1)-t)^3 ...
+ ((y(i)-c(i)*(h^2)/3)*(x(i+1)-t) + (y(i+1)-c(i+1)*(h^2)/3)*(t-x(i)))/h;
end

% 确定S(x)的值和导数
Sx = subs(S, t, 0.25);
Sx1 = diff(S, t);
Sx1 = subs(Sx1, t, 0.25);
Sx2 = diff(S, t, 2);
Sx2 = subs(Sx2, t, 0.53);

% 输出结果
fprintf('S(x) = %s\n', char(S));
fprintf('S(0.25) = %f\n', double(Sx));
fprintf('S''(0.25) = %f\n', double(Sx1));
fprintf('S''''(0.53) = %f\n', double(Sx2));