Is there a way to store execution times on a disk?

I am coding a program that add integer numbers, from 1 to N, one by one, where N is supposed to be an input.

However, I am also given the task of having the program take each intermediate result, storing them onto a disk, and report on execution times.

The first part is working out well, but I have no clue how to do the second part. Is this task possible for MATLAB to do?

So far, I have:

function fact = addInteger(n)
    fact = 0; 
    for i = 1:n 
        fact = fact + i; 
    end
end

Answer 1

[Star Strider]

Perhaps tic and toc —

s(1) = 0;
t0 = tic;
for k = 2:10
    s(k) = s(k-1) + 1;
    t_int(k) = toc(t0);
end
Result = [s; t_int]

Result = 2×10

0 1.0000 2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000 0 0.0023 0.0027 0.0028 0.0028 0.0034 0.0036 0.0036 0.0036 0.0036

N = 10;
s = zeros(1,N);                                 % Preallocate
t0 = tic;
for k = 2:10
    s(k) = s(k-1) + 1;
    t_int(k) = toc(t0);
end
Result = [s; t_int]

Result = 2×10

0 1.0000 2.0000 3.0000 4.0000 5.0000 6.0000 7.0000 8.0000 9.0000 0 0.0009 0.0010 0.0010 0.0010 0.0012 0.0013 0.0013 0.0013 0.0013

.

[Steven Deng]

This answer does store the time, but I meant "storing intermediate results" as in reading out on each output that comes out of the for loop, and also reading out the time it took to produce them.

So the output would be something like

1.0000 3.0000 6.0000 10.0000 .....

0.0009 0.0010 0.0010 0.0010 .....

[Star Strider]

I am not certain what you want. Putting the initial tic call in the loop is one option —

format longG
s(1) = 0;
for k = 2:10
    t0 = tic;
    s(k) = s(k-1) + 1;
    t_int(k) = toc(t0);
end
Result = [s; t_int]

Result = 2×10

0 1 2 3 4 5 6 7 8 9 0 0.000445 0.000141 3.2e-05 2.9e-05 0.000572 3e-06 1e-06 1e-06 2e-06

N = 10;
s = zeros(1,N);                                 % Preallocate
for k = 2:10
    t0 = tic;
    s(k) = s(k-1) + 1;
    t_int(k) = toc(t0);
end
Result = [s; t_int]

Result = 2×10

0 1 2 3 4 5 6 7 8 9 0 0.000208 3.3e-05 2.6e-05 2.6e-05 0.000255 2e-06 1e-06 1e-06 1e-06

This also demonstrates the benefit of preallocation.

.

[Steven Deng]

I managed to figure it out, I meant something like this:

function fact = addInteger2(n)
    s(1) = 0;
    t0 = tic;
        for k = 2:n+1
        s(k) = s(k-1) + (k-1);
        t_int(k) = toc(t0);
    end
Result = [s; t_int]
end

I wanted to add each consecutive integer, but at the same time, timing the results, so I could produce something like this:

addInteger2(4)

Result =

0 1.0000 3.0000 6.0000 10.0000

0 0.0005 0.0008 0.0009 0.0010

Thanks for your help, really appreciated it!

[Star Strider]

My pleasure!

I don’t see how your code differs significantly from mine, though, at least with respect to the tic and toc calls.

If my Answer helped you solve your problem, please Accept it!

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