\(\newcommand{\W}[1]{ \; #1 \; }\) \(\newcommand{\R}[1]{ {\rm #1} }\) \(\newcommand{\B}[1]{ {\bf #1} }\) \(\newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} }\) \(\newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} }\) \(\newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} }\) \(\newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }\)
speed_test¶
View page sourceRun One Speed Test and Return Results¶
Syntax¶
include <cppad/utility/speed_test.hpp>speed_test ( test , size_vec , time_min )See Also¶
Purpose¶
The speed_test function executes a speed test
for various sized problems
and reports the rate of 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 speed_test
automatically determines how many times to
repeat the section of the test that we wish to time.
Include¶
The file cppad/utility/speed_test.hpp defines the
speed_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.
Vector¶
We use Vector to denote a
simple vector class with elements
of type size_t .
test¶
The speed_test argument test is a function with the syntax
test ( size , repeat )
and its return value is void .
size¶
The test argument size has prototype
size_tsize
It specifies the size for this test.
repeat¶
The test argument repeat has prototype
size_trepeat
It specifies the number of times to repeat the test.
size_vec¶
The speed_test argument size_vec has prototype
constVector & size_vec
This vector determines the size for each of the tests problems.
time_min¶
The argument time_min has prototype
doubletime_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 is reached.
rate_vec¶
The return value rate_vec has prototype
Vector & rate_vec
We use \(n\) to denote its size which is the same as the vector size_vec . For \(i = 0 , \ldots , n-1\),
rate_vec [ i ]
is the ratio of repeat divided by time in seconds for the problem with size size_vec [ i ] .
Timing¶
If your system supports the unix gettimeofday function,
it will be used to measure time.
Otherwise,
time is measured by the difference in
(double) clock() / (double) CLOCKS_PER_SEC
in the context of the standard <ctime> definitions.
Example¶
The routine speed_test.cpp is an example and test
of speed_test .