Timing

Several methods exist for timing program execution in MATLAB.

cputime Method

cputime returns the CPU time used since MATLAB started; subtracting two values gives the CPU time spent on the code in between.

tic and toc form a pair of stopwatch timer functions. Basic syntax:

tic
% Code block
toc

tic records the start time and passes it to toc automatically; toc then returns the elapsed time.

When multiple tic/toc pairs are needed, you must capture the value of tic manually and feed it into the corresponding toc.

timeit returns the average elapsed time after running the input function repeatedly; it takes a function handle as input.

cputime returns CPU time, while timeit and tic/toc return wall-clock time
- CPU time for the pause function is typically small, but the wall-clock time accounts for the actual time that MATLAB execution is paused
- The cputime function measures the total CPU time and sums across all threads
  - If your function uses four processing cores equally, the CPU time could be approximately four times higher than the wall-clock time
Unlike tic/toc, the timeit function calls your code multiple times, and therefore considers first-time costs