are cell arrays slow?

[Bertrand Roessli]

Hello,

I have tried the following test code and I have the 
feeling that working with cell arrays is slow. Do I make a mistake 
somewhere? 


nr=1000;

for i=1:nr
        mom.mx=i;  
        mom.my=2*i;
        a{i}=mom;
endfor


tic;
[[a{1:nr}].mx].+[[a{1:nr}].my];
toc

tic;
b=[a{1:nr}];   
[b.mx].+[b.my];
toc


tic;
for i=1:nr
        a{i}.mx.+a{i}.my;
endfor
toc   

tic;
i=1:nr;
b=[a{i}];
[b.mx].+[b.my];
toc

    
tic;
i=1:nr;
[i].+2.*[i];
toc

Elapsed time is 0.803093 seconds.
Elapsed time is 0.391693 seconds.
Elapsed time is 0.049988 seconds.
Elapsed time is 0.388489 seconds.
Elapsed time is 0.000381 seconds.

What puzzles me is that the for-loop is faster. 

Thank you,


B. Roessli



-- 
Dr. Bertrand Roessli
Laboratory for Neutron Scattering
Paul Scherrer Institut and ETH Zurich
CH-5232 Villigen PSI

Tel.: +41 56 310 44 01