Time a function
You are encouraged to solve this task according to the task description, using any language you may know.
What time does it take to execute a `function' with a given `arguments'.
Use a timer with the least granularity available on your system.
What caveats are there?
This task is intended as a subtask for Measure relative performance of sorting algorithms implementations.
Python
Interpreter: Python
Given function and arguments return a time (in microseconds) it takes to make the call.
Note: There is an overhead in executing a function that does nothing.
def usec(function, arguments):
modname, funcname = __name__, function.__name__
timer = timeit.Timer(stmt='%(funcname)s(*args)' % vars(),
setup='from %(modname)s import %(funcname)s; args=%(arguments)r' % vars())
try:
t, N = 0, 1
while t < 0.2:
t = min(timer.repeat(repeat=3, number=N))
N *= 10
microseconds = round(10000000 * t / N, 1) # per loop
return microseconds
except:
timer.print_exc(file=sys.stderr)
raise
def nothing(): pass def identity(x): return x
Example
>>> print usec(nothing, []) 1.7 >>> print usec(identity, [1]) 2.2 >>> print usec(pow, (2, 100)) 3.3 >>> print map(lambda n: str(usec(qsort, (range(n),))), range(10)) ['2.7', '2.8', '31.4', '38.1', '58.0', '76.2', '100.5', '130.0', '149.3', '180.0']
where qsort() implemented on Quicksort page. Timings show that the implementation of qsort() has quadratic dependence on time for already sorted sequences (instead of O(N*log(N)) on average).