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| 21 | <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> |
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| 22 | <div class="fragment"><pre class="fragment"><span class="preprocessor">#include <itpp/itbase.h></span> |
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| 23 | |
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| 24 | <span class="keyword">using namespace </span>itpp; |
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| 25 | |
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| 26 | <span class="comment">//These lines are needed for use of cout and endl</span> |
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| 27 | <span class="keyword">using</span> std::cout; |
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| 28 | <span class="keyword">using</span> std::endl; |
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| 29 | |
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| 30 | <span class="keywordtype">int</span> main() |
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| 31 | { |
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| 32 | <span class="comment">//Declare the scalars used:</span> |
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| 33 | <span class="keywordtype">long</span> i, sum, N; |
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| 34 | |
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| 35 | <span class="comment">//Declare tt as an instance of the timer class:</span> |
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| 36 | Real_Timer tt; |
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| 37 | |
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| 38 | <span class="comment">//Initiate the variables:</span> |
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| 39 | N = 1000000; |
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| 40 | sum = 0; |
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| 41 | |
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| 42 | <span class="comment">//Start and reset the timer:</span> |
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| 43 | tt.tic(); |
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| 44 | |
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| 45 | <span class="comment">//Do some processing</span> |
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| 46 | <span class="keywordflow">for</span> (i = 0; i < N; i++) { |
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| 47 | sum += i; |
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| 48 | } |
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| 49 | |
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| 50 | <span class="comment">// Print the elapsed time</span> |
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| 51 | tt.toc_print(); |
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| 52 | |
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| 53 | <span class="comment">//Print the result of the processing:</span> |
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| 54 | 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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| 55 | |
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| 56 | <span class="comment">//Exit program:</span> |
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| 57 | <span class="keywordflow">return</span> 0; |
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| 58 | |
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| 59 | } |
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| 60 | </pre></div><p> |
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| 61 | When you run this program, the output will look something like this:<p> |
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| 62 | <div class="fragment"><pre class="fragment">Elapsed time = 0.000797055 seconds |
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| 63 | The sum of all integers from 0 to 999999 equals 1783293664 |
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| 64 | </pre></div> </div> |
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