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'（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];

% 计算二阶导数
h = diff(x);
delta = diff(y) ./ h;
D = 2 * (diff(delta) ./ (h(1:end-1) + h(2:end)));

% 构造矩阵方程
n = length(x);
A = zeros(n);
A(1,1:2) = [1, 0];
A(n,n-1:n) = [0, 1];
for i = 2:n-1
A(i,i-1:i+1) = [h(i-1), 2*(h(i-1)+h(i)), h(i)];
end
B = [0; D; 0];

% 解矩阵方程
c = A \ B;

% 计算系数
d = (c(2:end) - c(1:end-1)) ./ (3*h);
b = delta - h.*(2*c(1:end-1) + c(2:end))/3;
a = y(1:end-1);

% 构造插值函数
syms t;
S = cell(1,n-1);
for i = 1:n-1
S{i} = a(i) + b(i)*(t-x(i)) + c(i)*(t-x(i))^2 + d(i)*(t-x(i))^3;
end

% 求解限制条件
syms x1 x2;
eqns = [subs(diff(S{1},t),t,x1) == 1, subs(diff(S{end},t,2),t,x2) == 0.6868];
vars = [x1, x2];
sol = solve(eqns, vars);

% 输出插值函数和限制条件
for i = 1:n-1
disp(['S',num2str(i-1),'(x) = ',char(S{i})]);
end
disp(['S''(',num2str(sol.x1),') = 1']);
disp(['S''''(',num2str(sol.x2),') = 0.6868']);

% 绘制插值函数
t = linspace(x(1),x(end),1000);
figure;
hold on;
plot(x,y,'o','MarkerSize',10);
for i = 1:n-1
plot(t,subs(S{i},t),'LineWidth',2);
end
xlabel('x');
ylabel('y');
legend('Data','S0(x)','S1(x)','S2(x)','S3(x)','S4(x)');