没有足够的输入参数Matlab

Question

这是夹紧的三次样条代码，但在第一行（ n = length(X);）标记错误，MATLAB说没有足够的输入参数，说实话，我不知道为什么。有人帮帮我。

function [a,b,c,d]=ClampedCubicSpline(X,a,FPO,FPN)        
n = length(X);        
m = length (a);        
for i=1:n;        
    a(i)=X(2,i);        
end        

for i=1:n-1;        
   h(i)=X(1,i+1)-X(1,i);        
end        

alpha(1) = (3/hi(1))*(a(2)-a(1)) - 3 * FPO;        
alpha(n) = 3*FPN - (3/hi(n-1))*(a(n)-a(n-1));        
for i=2:n-1;        
    alpha(i)=3/h(i)*(a(i+1)-a(i))-3/h(i-1)*(a(i)-a(i-1));        
end    
l(1)=2*h(1);        
mu(1)=.5;        
z(1)=alpha(1)/l(1);        
for i=2:n-1;        
    l(i)=2*(X(1,i+1)-X(1,i-1))-h(i-1)*mu(i-1);        
    mu(i)=h(i)/l(i);        
    z(i)=(alpha(i)-h(i-1)*z(i-1))/l(i);        
end        

l(n)=h(n-1)*(2-mu(n-1));        
z(n)=(alpha(n)-h(n-1)*z(n-1))/l(n);       
c(n)=z(n);      

for i=n-1:-1:1;        
    c(i)=z(i)-mu(i)*c(i+1); 
    b(i)=(a(i+1)-a(i))/h(i)-h(i)*(c(i+1)+2*c(i))/3; 
    d(i)=(c(i+1)-c(i))/(3*h(i)); 
end
for i=1:n-1;        
    x=X(1,i):0.1:X(1,i+1); 
    y=a(i)+b(i)*(x-X(1,i))+c(i)*(x-X(1,i)).^2+d(i)*(x-X(1,i)).^3; 
    hold on; 
    plot(x,y,'b'); 
end

here the screenShot