| 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
|---|
| 2 | <html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> |
|---|
| 3 | <title>mixpp: Using timers to measure execution time</title> |
|---|
| 4 | <link href="tabs.css" rel="stylesheet" type="text/css"> |
|---|
| 5 | <link href="doxygen.css" rel="stylesheet" type="text/css"> |
|---|
| 6 | </head><body> |
|---|
| 7 | <!-- Generated by Doxygen 1.5.8 --> |
|---|
| 8 | <script type="text/javascript"> |
|---|
| 9 | <!-- |
|---|
| 10 | function changeDisplayState (e){ |
|---|
| 11 | var num=this.id.replace(/[^[0-9]/g,''); |
|---|
| 12 | var button=this.firstChild; |
|---|
| 13 | var sectionDiv=document.getElementById('dynsection'+num); |
|---|
| 14 | if (sectionDiv.style.display=='none'||sectionDiv.style.display==''){ |
|---|
| 15 | sectionDiv.style.display='block'; |
|---|
| 16 | button.src='open.gif'; |
|---|
| 17 | }else{ |
|---|
| 18 | sectionDiv.style.display='none'; |
|---|
| 19 | button.src='closed.gif'; |
|---|
| 20 | } |
|---|
| 21 | } |
|---|
| 22 | function initDynSections(){ |
|---|
| 23 | var divs=document.getElementsByTagName('div'); |
|---|
| 24 | var sectionCounter=1; |
|---|
| 25 | for(var i=0;i<divs.length-1;i++){ |
|---|
| 26 | if(divs[i].className=='dynheader'&&divs[i+1].className=='dynsection'){ |
|---|
| 27 | var header=divs[i]; |
|---|
| 28 | var section=divs[i+1]; |
|---|
| 29 | var button=header.firstChild; |
|---|
| 30 | if (button!='IMG'){ |
|---|
| 31 | divs[i].insertBefore(document.createTextNode(' '),divs[i].firstChild); |
|---|
| 32 | button=document.createElement('img'); |
|---|
| 33 | divs[i].insertBefore(button,divs[i].firstChild); |
|---|
| 34 | } |
|---|
| 35 | header.style.cursor='pointer'; |
|---|
| 36 | header.onclick=changeDisplayState; |
|---|
| 37 | header.id='dynheader'+sectionCounter; |
|---|
| 38 | button.src='closed.gif'; |
|---|
| 39 | section.id='dynsection'+sectionCounter; |
|---|
| 40 | section.style.display='none'; |
|---|
| 41 | section.style.marginLeft='14px'; |
|---|
| 42 | sectionCounter++; |
|---|
| 43 | } |
|---|
| 44 | } |
|---|
| 45 | } |
|---|
| 46 | window.onload = initDynSections; |
|---|
| 47 | --> |
|---|
| 48 | </script> |
|---|
| 49 | <div class="navigation" id="top"> |
|---|
| 50 | <div class="tabs"> |
|---|
| 51 | <ul> |
|---|
| 52 | <li><a href="main.html"><span>Main Page</span></a></li> |
|---|
| 53 | <li class="current"><a href="pages.html"><span>Related Pages</span></a></li> |
|---|
| 54 | <li><a href="modules.html"><span>Modules</span></a></li> |
|---|
| 55 | <li><a href="annotated.html"><span>Classes</span></a></li> |
|---|
| 56 | <li><a href="files.html"><span>Files</span></a></li> |
|---|
| 57 | </ul> |
|---|
| 58 | </div> |
|---|
| 59 | <div class="navpath"><a class="el" href="manual.html">User Manual</a> |
|---|
| 60 | </div> |
|---|
| 61 | </div> |
|---|
| 62 | <div class="contents"> |
|---|
| 63 | <h1><a class="anchor" name="timer">Using timers to measure execution time </a></h1>In this example we are using the Real_Timer class to measure the execution time of a simple program. The Real_Timer class is included in the itmisc library.<p> |
|---|
| 64 | <div class="fragment"><pre class="fragment"><span class="preprocessor">#include <itpp/itbase.h></span> |
|---|
| 65 | |
|---|
| 66 | <span class="keyword">using namespace </span>itpp; |
|---|
| 67 | |
|---|
| 68 | <span class="comment">//These lines are needed for use of cout and endl</span> |
|---|
| 69 | <span class="keyword">using</span> std::cout; |
|---|
| 70 | <span class="keyword">using</span> std::endl; |
|---|
| 71 | |
|---|
| 72 | <span class="keywordtype">int</span> main() |
|---|
| 73 | { |
|---|
| 74 | <span class="comment">//Declare the scalars used:</span> |
|---|
| 75 | <span class="keywordtype">long</span> i, sum, N; |
|---|
| 76 | |
|---|
| 77 | <span class="comment">//Declare tt as an instance of the timer class:</span> |
|---|
| 78 | Real_Timer tt; |
|---|
| 79 | |
|---|
| 80 | <span class="comment">//Initiate the variables:</span> |
|---|
| 81 | N = 1000000; |
|---|
| 82 | sum = 0; |
|---|
| 83 | |
|---|
| 84 | <span class="comment">//Start and reset the timer:</span> |
|---|
| 85 | tt.tic(); |
|---|
| 86 | |
|---|
| 87 | <span class="comment">//Do some processing</span> |
|---|
| 88 | <span class="keywordflow">for</span> (i = 0; i < N; i++) { |
|---|
| 89 | sum += i; |
|---|
| 90 | } |
|---|
| 91 | |
|---|
| 92 | <span class="comment">// Print the elapsed time</span> |
|---|
| 93 | tt.toc_print(); |
|---|
| 94 | |
|---|
| 95 | <span class="comment">//Print the result of the processing:</span> |
|---|
| 96 | cout << <span class="stringliteral">"The sum of all integers from 0 to "</span> << N - 1 << <span class="stringliteral">" equals "</span> << sum << endl; |
|---|
| 97 | |
|---|
| 98 | <span class="comment">//Exit program:</span> |
|---|
| 99 | <span class="keywordflow">return</span> 0; |
|---|
| 100 | |
|---|
| 101 | } |
|---|
| 102 | </pre></div><p> |
|---|
| 103 | When you run this program, the output will look something like this:<p> |
|---|
| 104 | <div class="fragment"><pre class="fragment">Elapsed time = 0.000797055 seconds |
|---|
| 105 | The sum of all integers from 0 to 999999 equals 1783293664 |
|---|
| 106 | </pre></div> </div> |
|---|
| 107 | <hr size="1"><address style="text-align: right;"><small>Generated on Tue Jun 2 10:11:00 2009 for mixpp by |
|---|
| 108 | <a href="http://www.doxygen.org/index.html"> |
|---|
| 109 | <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.8 </small></address> |
|---|
| 110 | </body> |
|---|
| 111 | </html> |
|---|
