清空筛选条件
清空筛选条件

Hi, i need to find out the eigenvalues of a 8000x8000 matrix system by eig() function of matlab?? may i know the normal simulation time of the eig() function of such a huge matrix in MATLAB?

5 次查看（过去 30 天）
Kamanashis Saha
Kamanashis Saha 2016-9-6
编辑： John D'Errico 2016-9-6
Hi, i need to find out the eigenvalues of a 8000x8000 matrix system by eig() function of matlab?? may i know the normal simulation time of the eig() function of such a huge matrix in MATLAB?

请先登录，再回答此问题。

回答（2 个）

George
George 2016-9-6
It's going to depend on the matrix, correct?
Running a simulation on my machine (Surface Pro3) I was able to modify the example from the eig() documentation to use a 8000x8000 matrix. It calculated the eigenvalues in ~44sec.
John D'Errico
John D'Errico 2016-9-6
编辑：John D'Errico 2016-9-6
The normal time is 42. I'm not sure what the units are though. :)
How can we tell you the "normal time" to compute eigenvalues? It will depend on what computer you have. It will depend on the speed of that computer. It will depend on how much RAM you have. It will depend on the matrix. (If your matrix is diagonal, this will go pretty fast.)
If you really want to know the "normal" time for your computer, then time eig for a series of smaller nxn matrices, and extrapolate the time up to n=8000.
t = NaN(1,1800);
N = 100:100:1800;
for n = N
A = randn(n);
t(n) = timeit(@() eig(A));
end
loglog(N,t(N),'o')
grid on
p = polyfit(log(N),log(t(N)),1)
p =
2.1406 -14.748
exp(polyval(p,log(8000)))
ans =
89.16
So, on MY computer, I'd expect it to take roughly 1.5 minutes, unless it starts to have memory problems.

类别

在 Help Center 和 File Exchange 中查找有关 Linear Algebra 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by