Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

Solution 292535

Submitted on 30 Jul 2013 by Claudio Gelmi

Correct

20Size
Leading solution size is 3.
This solution is locked. To view this solution, you need to provide a solution of the same size or smaller.

This solution is outdated. To rescore this solution, log in.

Test Suite

Test
Code Input and Output
1
Pass
 
feval(@assignin,'caller','score',30); %

                    
2
Pass
 
%%
tic
assert(isequal(primes_faster(1),primes(1)))
assert(isequal(primes_faster(2),primes(2)))
for i=1:100
 n=randi(2000,1);
 assert(isequal(primes_faster(n),primes(n)))
end
toc
Elapsed time is 0.036376 seconds.
3
Pass
 
%%
tic
ta=clock;
 p = primes_faster(2^28);
t1=etime(clock,ta); % time in sec
fprintf('P 2^28 %12i %10.3f\n',length(p),t1)
assert(isequal(size(unique(p),2),14630843))
ptr=randi(7603553,1,10); % small to avoid timeout
pchk=p(ptr);
assert(all(isprime(pchk)))
feval(  @assignin,'caller','score',floor(min(30,t1))  );
toc
P 2^28     14630843     20.553
Elapsed time is 23.913231 seconds.