Matrix 2-norm Condition number
显示 更早的评论
I wanted to compare the result of the fucntion [cond();] which retrun the matrix 2-norm condition number as a ratio between the largest and the smallest singular value using the [isequal();] function with the result "segma" matrix of the SVD out of [svd();] fucntion as:
A = [1 2 5;4 8 7;8 9 5]; % example
[u,s,v] = svd(A);
c_num = cond(A);
sing_ratio = s(1,1)/s(end,end);
isequal(c_num, sing_ratio);
and the reslut was [0] although they are the same, and sadly this isn't the first tine that the equal function fails with me and don't know the reason.
采纳的回答
sadly this isn't the first tine that the equal function fails with me and don't know the reason.
The isequal() function didn't fail. The two results are different ... just not by very much:
>> percent_difference=abs(c_num - sing_ratio)./c_num*100,
percent_difference =
2.4864e-14
If you want to know how cond() is computed, you can just read it:
>> type cond.m
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Linear Algebra 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
