TIMEIT Benchmarking Function

Andy, I don't fully understand your question. What do you mean by "warm in the time," for example? But I would guess that you're looking for something like this:

x = zeros(1024, 1024);
timeit(@() fft2(x))

This is extremely useful, but since it requires a function definition, you must either use lambdas, which don't allow procedural code (ie, a list of statements), define a local function, which means you have to turn your script into a function file (sometimes not desirable when dealing with workspace variables), or create a new file (lots of throwaway files with simple routines).

I wonder if it would be possible to add the following functionality (either in the same function or through a different one) :

while timeit %returns true when a new measurement is needed
... my procedural code ...
... multiple lines, will run as many times as timeit() sees fit ...
end
result = timeit; %next call: return result. reset state.

As you can see, this sort of usage would be tremendously useful to just profile a piece of code with no extra details -- just wrap it in a loop. Of course, it's only fair if you conclude it's not worth the additional effort :)

A suggestion to improve accuracy when you measure small execution times. I believe it would be useful to subtract from median(times) the time needed for the inner iterations (“offset”). Here is the code:

[…omissis…]
offsets = zeros(num_outer_iterations, 1);
times = offsets;
for k = 1:num_outer_iterations
t1 = tic;
for p = 1:num_inner_iterations
end
offsets(k) = toc(t1);
end

for k = 1:num_outer_iterations
t1 = tic;
for p = 1:num_inner_iterations
[outputs{:}] = f();
end
times(k) = toc(t1);
end

t = (median(times-offsets)) / num_inner_iterations;
[…omissis…]

This offset is not always negligible, especially when you want to time the execution of very quick commands or functions. Notice that the value of each element of variable “offsets” also include the time needed to execute

t1 = tic; times(k) = toc(t1);

On my system, this is very small (1.7321e-005 s), but not negligible when testing the execution of very quick commands, such as RESHAPE.

Paolo de Leva

Small remark - nargout parameter is sometimes less than 0. I had -1 result when there was no output arguments from function.

In case of problems with error "Too many output argument" juz change line :
num_outputs = ~(nargout(f) == 0);
to
num_outputs = ~(nargout(f) <= 0);

Still excellent file!