[Octave-bug-tracker] [bug #61674] deconv much slower than conv

[Dmitri A. Sergatskov]

Follow-up Comment #6, bug #61674 (project octave):

Here is the benchmark I tried (my scenario is that 
I accidentally use length of the windows the same as lenfth the signal itself
/ 2):


wlen = 3*1e3
l = 2*wlen;
t = linspace(-100*pi,100*pi,300*1e5);
x = sin(t) + 0.25*rand(size(t));
b = (1/wlen)*ones(1,wlen);
a = 1;
tic;
y = filter(b,a,x);
toc


The speedup of patch2 is comparable to v1 (73 sec vs 13.6 sec).
But here is me realising something is wrong and hitting Chtrl-C:


octave:2> filt_benchl
wlen = 3000
Elapsed time is 13.6168 seconds.
octave:3> filt_benchl
wlen = 3000
^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C
octave:4> 


I think delay of a couple sec is acceptable, but longer than that and you will
get complains/bug reports etc...
The delay is pre predictable when there is  a simple arithmetic 
expression in the loop and you check for interrupts every
N loops or something like that.

Dmitri.
-- 



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