In Reply to: Re: 提示:有關作業二的第二題 posted by Chong-ming on March 11, 1997 at 22:04:34:
> 每日一字 "Hilbert matrix"
> Hilbert matrix is the N by N matrix with elements
> which equal to 1/(i+j-1)
> for迴圈版本:
> FOR I = 1:N,
> FOR J = 1:N,
> A(I,J) = 1/(I+J-1);
> END
> END
> vector運算版本
> J = 1:n;
> J = J(ones(n,1),:);
> I = J';
> E = ones(n,n);
> H = E./(I+J-1);
> 看得用力一點,就會明白vector運算是如何利用
> 【空間換取時間】了。
可是用hilbert matrix一點也不節省時間,而且還會造
成out of memory的情形。