Prev

Next

Index-> contents reference index search external

Up-> CppAD utility time_test

Headings-> Syntax Purpose Motivation Include test ---..size ---..repeat time_min test_size repeat_out time Timing Example

@(@\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }@)@ This is cppad-20221105 documentation. Here is a link to its current documentation . Determine Amount of Time to Execute a Test
Syntax
# include <cppad/utility/time_test.hpp>
time = time_test(test, time_min)
time = time_test(test, time_min, test_size)
time = time_test(test, time_min, test_size, repeat_out)

Purpose
The time_test function executes a timing test and reports the amount of wall clock time for execution.

Motivation
It is important to separate small calculation units and test them individually. This way individual changes can be tested in the context of the routine that they are in. On many machines, accurate timing of a very short execution sequences is not possible. In addition, there may be set up and tear down time for a test that we do not really want included in the timing. For this reason time_test automatically determines how many times to repeat the section of the test that we wish to time.

Include
The file cppad/utility/time_test.hpp defines the time_test function. This file is included by cppad/cppad.hpp and it can also be included separately with out the rest of the CppAD routines.

test
The time_test argument test is a function, or function object. In the case where test_size is not present, test supports the syntax
    test(repeat)
In the case where test_size is present, test supports the syntax
    test(size, repeat)
In either case, the return value for test is void.

size
If the argument size is present, it has prototype
    size_t size
and is equal to the test_size argument to time_test.

repeat
The test argument repeat has prototype
    size_t repeat
It specifies the number of times to repeat the test.

time_min
The argument time_min has prototype
    double time_min
It specifies the minimum amount of time in seconds that the test routine should take. The repeat argument to test is increased until this amount of execution time (or more) is reached.

test_size
If this argument is present, it argument has prototype
    size_t test_size
In this case test_size will be present, and have the same value, in each call to test .

repeat_out
If this argument is present, it has prototype
    size_t& repeat_out
This input value of this argument does not matter. Upon return, it is the value of repeat that corresponds to the return value time ; i.e., the actual total time of the test is
    total_time = repeat * time

time
The return value time has prototype
    double time
and is the number of wall clock seconds that it took to execute test divided by the value used for repeat .

Timing
The routine elapsed_seconds will be used to determine the amount of time it took to execute the test.

Example
The routine time_test.cpp is an example and test of time_test.

---

Input File: include/cppad/utility/time_test.hpp