[交流] 【致H兄】数列题的万能多项式拟合求法 已有2人参与

function av = myPolyFit(y)
%A * av = y
    n = length(y);
    y = y(:); %make `y` a column vector
   
    %construct `A`
    A = (1:n)' * ones(1,n);
    for j = n-2 :-1: 1
        A(:,j) = A(:,j) .* A(:,j+1);
    end
    A(:,n) = ones(n,1);
   
    av = A\y;

y=[22 26 20 23 24 21 20 18];
av=myPolyFit(y);
n=1:0.001:9;
val=polyval(av, n);
poly2str(av, 'n')
plot(n, val)

   0.0047619 n^7 - 0.18889 n^6 + 3.025 n^5 - 25.1806 n^4 + 116.3583 n^3
   - 293.6306 n^2 + 365.6119 n - 144

14楼: Originally posted by sudo at 2011-09-09 22:46:22:
=,=咳，取模的话，周期性完美出现...然后对称性也有了....

其实我才是那个刻板的教条主义者
[ Last edited by sudo on 2011-9-9 at 22:47 ]

1楼: Originally posted by sudo at 2011-09-09 16:11:12:
中秋快到了无心工作，就娱乐一下吧~

不知道是怎么回事的虫友请看这个帖子：
http://muchong.com/bbs/viewthread.php?tid=3573558&fpage=0&view=&highlight=&page=1

分析也在那 ...