How to store values from toc into an array

2018 2 7
1 个回答
更新时间：2018 2 7
15 次查看（30 天）

回答（1 个）

Walter Roberson
Walter Roberson 2018-2-7

3 个投票

tic;
for K = 1 : 10
times(K) = toc;
end

6 个评论
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Raiven Balderas
Raiven Balderas 2018-2-7
编辑：Walter Roberson 2018-2-7
%HW3.m
im trying to do question 5 of my homework but it isn't working. the homework question is provided in link/attachment
counter=0;
for n=[1E1 1E2 1E3 1E4 1E5]
timeslow=zeros(1,5)
tic;p=prime_list_slow_class(n);timeslow=toc
counter=counter+1;
end
counter=1;
for n=[1E1 1E2 1E3 1E4 1E5]
timeslist=zeros(1,5);
tic;p=prime_list(n);timeslist =toc
counter=counter+1;
end
counter=2;
for n=[1E1 1E2 1E3 1E4 1E5]
timesieve=zeros(1,5);
tic;p=prime_sieve(n);timesieve=toc
counter=counter+1;
end
figure(3);
hold on;
loglog(timeslow,[1E1 1E2 1E3 1E4 1E5],'b-','linewidth',3); hold on
loglog(timeslist,[1E1 1E2 1E3 1E4 1E5],'r-','linewidth',3); hold on
loglog(timesieve,[1E1 1E2 1E3 1E4 1E5],'g-','linewidth',3); hold on
Walter Roberson
Walter Roberson 2018-2-7
You are overwriting all of timeslow, timeslist, timesieve each iteration of the loop.
for N = 1 : 5
n = 10^N;
...
timeslow(n) = toc;
...
end
Raiven Balderas
Raiven Balderas 2018-2-7
still not plotting,nor working. thanks though.
Walter Roberson
Walter Roberson 2018-2-7
Only initialize timeslow to zero before the for loop, not in the for loop.
Raiven Balderas
Raiven Balderas 2018-2-7
thanks, how do i do the bonus ?
Walter Roberson
Walter Roberson 2018-2-7
编辑：Walter Roberson 2018-2-7
You write a function named prime_count that takes n as an input and returns a vector named Upsilon which is of length n, each element of which is the number of prime numbers less than or equal to its index. The function prime_count must call prime_sieve exactly once -- however, it is not required that your function use the results returned by prime_sieve .

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