[Octave-bug-tracker] [bug #43519] eigs really slow compared to Matlab

[RUILIN CHU]

Follow-up Comment #2, bug #43519 (project octave):

I can confirm it's not a memory issue
So I tried a rather sparse matrix
%L=8000
a=rand(L)>0.95;
b=a+a'+0.001*eye(L);
c=sparse(b);
tic; e=eigs(b); toc
tic; e=eigs(c); toc

L=1000;
test
Elapsed time is 0.0945721 seconds.
Elapsed time is 0.841012 seconds.

L=2000;
>> test
Elapsed time is 0.632753 seconds.
Elapsed time is 4.99704 seconds.

 L=3000;
>> test
Elapsed time is 1.71377 seconds.
Elapsed time is 13.1236 seconds.

L=4000;
>> test
Elapsed time is 3.08764 seconds.
Elapsed time is 27.1122 seconds.

L=5000;
>> test
Elapsed time is 4.88847 seconds.
Elapsed time is 43.0939 seconds.

L =  6000
>> test
Elapsed time is 8.19819 seconds.
Elapsed time is 65.2827 seconds.

whos
Variables in the current scope:

   Attr Name        Size                     Bytes  Class
   ==== ====        ====                     =====  =====
        L           1x1                          8  double
        a        6000x6000                36000000  logical
        b        6000x6000               288000000  double
        c        6000x6000                42251956  double
        e           6x1                         48  double

Total is 75519003 elements using 366252012 bytes


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