How to create a graph time vs value n

12 次查看（过去 30 天）
Emilia
Emilia 2020-12-3
评论： Emilia 2020-12-3
Hello,
I have a function that we enter a value n. Next I designed a matrix here and it measures time (tic,toc) until vector returns result.
Now I want to produce a graph for 4<=n<=50 vs time, How can this created?
Thanks for the helpers :)
function [A,VectorOut,B]= pp(n)
tic
f=4*ones(1,n^2);
m=diag(f);
x = zeros(1,n^2);
x_new = x;
j=0;
while j~=n^2
[m(j+1,j+2)]=-1;
[m(j+1,j+4)]=-1;
[m(j+2,j+1)]=-1;
[m(j+4,j+1)]=-1;
j=j+1 ;
end
t=m(1:n^2,1:n^2);
v=zeros(1,n^2);
v(1)=1;
v(n^2)=1;
A=t;
B=v';
for i = 1:n^2
x_new(i) = (B(i) - sum(A(i,1:i-1).*x_new(1:i-1)) - sum(A(i,i+1:n).*x(i+1:n)))/A(i,i);
end
VectorOut=x_new'
toc
end

请先登录，再回答此问题。

回答（2 个）

Ameer Hamza
Ameer Hamza 2020-12-3
编辑：Ameer Hamza 2020-12-3
I think it might be better if you move the tic ... toc lines outside the function. For example, remove these lines and then run the following code
n = 4:50;
ts = zeros(size(n));
for i = 1:numel(n)
tic
[A,VectorOut,B]= pp(n(i));
ts(i) = toc;
end
plot(n, ts)
Alternatively, you will need to return the value of 't' too. For example,
function [A,VectorOut,B,t]= pp(n)
tic
f=4*ones(1,n^2);
.. ..
.. ..
.. ..
.. ..
.. ..
VectorOut=x_new'
t = toc
end
and then run the code
n = 4:50;
ts = zeros(size(n));
for i = 1:numel(n)
[A,VectorOut,B,ts(i)]= pp(n(i));
end
plot(n, ts)
Deepak Gupta
Deepak Gupta 2020-12-3
编辑：Deepak Gupta 2020-12-3
Hi Emilia,
Placed of toc in the function will just display the elapsed time there instead you need to return the elapsed time from this function, to the script where you will be called this function. i.e. in your function you can write.
totalTime = toc;
And then return it.
In your script you need to save these times with respect to n values. i.e.
n = 4:50;
totalTime = zeros(1, size(n));
for n
[~, ~, ~, nTime] = pp(n);
totalTime(n-3) = nTime;
end
Now you can plot time vs n.
plot(totalTime, n)
Hope this helps,
Cheers,
Deepak

类别

在 Help Center 和 File Exchange 中查找有关 MATLAB 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by