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| 67 | <h1><a class="anchor" id="timer">Using timers to measure execution time </a></h1><p>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> |
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| 68 | <div class="fragment"><pre class="fragment"><span class="preprocessor">#include <itpp/itbase.h></span> |
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| 69 | |
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| 70 | <span class="keyword">using namespace </span>itpp; |
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| 71 | |
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| 72 | <span class="comment">//These lines are needed for use of cout and endl</span> |
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| 73 | <span class="keyword">using</span> std::cout; |
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| 74 | <span class="keyword">using</span> std::endl; |
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| 75 | |
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| 76 | <span class="keywordtype">int</span> main() { |
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| 77 | <span class="comment">//Declare the scalars used:</span> |
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| 78 | <span class="keywordtype">long</span> i, sum, N; |
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| 79 | |
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| 80 | <span class="comment">//Declare tt as an instance of the timer class:</span> |
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| 81 | Real_Timer tt; |
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| 82 | |
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| 83 | <span class="comment">//Initiate the variables:</span> |
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| 84 | N = 1000000; |
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| 85 | sum = 0; |
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| 86 | |
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| 87 | <span class="comment">//Start and reset the timer:</span> |
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| 88 | tt.tic(); |
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| 89 | |
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| 90 | <span class="comment">//Do some processing</span> |
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| 91 | <span class="keywordflow">for</span> ( i = 0; i < N; i++ ) { |
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| 92 | sum += i; |
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| 93 | } |
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| 94 | |
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| 95 | <span class="comment">// Print the elapsed time</span> |
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| 96 | tt.toc_print(); |
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| 97 | |
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| 98 | <span class="comment">//Print the result of the processing:</span> |
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| 99 | cout << <span class="stringliteral">"The sum of all integers from 0 to "</span> << N - 1 << <span class="stringliteral">" equals "</span> << sum << endl; |
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| 100 | |
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| 101 | <span class="comment">//Exit program:</span> |
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| 102 | <span class="keywordflow">return</span> 0; |
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| 103 | |
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| 104 | } |
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| 105 | </pre></div><p>When you run this program, the output will look something like this:</p> |
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| 106 | <div class="fragment"><pre class="fragment">Elapsed time = 0.000797055 seconds |
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| 107 | The sum of all integers from 0 to 999999 equals 1783293664 |
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| 108 | </pre></div> </div> |
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