1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 5<head> 6<meta name="generator" content="HTML Tidy for Linux/x86 (vers 12 April 2005), see www.w3.org" /> 7<title>Priority Queue Text Modify (Down) Timing Test</title> 8<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> 9</head> 10<body> 11<div id="page"> 12<h1>Priority Queue Text <tt>modify</tt> Timing Test - II</h1> 13<h2><a name="description" id="description">Description</a></h2> 14<p>This test inserts a number of values with keys from an 15 arbitrary text ([ <a href="references.html#wickland96thirty">wickland96thirty</a> ]) into 16 into a container then modifies each one "down" (<i>i.e.,</i> it 17 makes it smaller). It uses <tt>modify</tt> for <tt>pb_ds</tt>'s 18 priority queues; for the STL's priority queues, it pops values 19 from a container until it reaches the value that should be 20 modified, then pushes values back in. It measures the average 21 time for <tt>modify</tt> as a function of the number of 22 values.</p> 23<p>(The test was executed with <a href="http://gcc.gnu.org/viewcvs/*checkout*/trunk/libstdc%2B%2B-v3/testsuite/performance/ext/pb_ds/priority_queue_text_modify_timing.cc"><tt>priority_queue_text_modify_down_timing_test</tt></a> 24 thirty_years_among_the_dead_preproc.txt 200 200 2100 f)</p> 25<h2><a name="purpose" id="purpose">Purpose</a></h2> 26<p>The main purpose of this test is to contrast <a href="priority_queue_text_modify_up_timing_test.html">Priority Queue 27 Text <tt>modify</tt> Timing Test - I</a>.</p> 28<h2><a name="results" id="results">Results</a></h2> 29<p>Figures <a href="#NPG">NPG</a>, <a href="#NPM">NPM</a>, and 30 <a href="#NPL">NPL</a> show the results for the native priority 31 queues and <tt>pb_ds</tt> 's priority queues in <a href="pq_performance_tests.html#gcc"><u>g++</u></a>, <a href="pq_performance_tests.html#msvc"><u>msvc++</u></a>, and 32 <a href="pq_performance_tests.html#local"><u>local</u></a>, 33 respectively; Figures <a href="#NRTG">NRTG</a>, <a href="#NRTM">NRTM</a>, and <a href="#NRTL">NRTL</a> show the results 34 for the pairing heap and thin heaps in <a href="pq_performance_tests.html#gcc"><u>g++</u></a>, <a href="pq_performance_tests.html#msvc"><u>msvc++</u></a>, and 35 <a href="pq_performance_tests.html#local"><u>local</u></a>, 36 respectively,</p> 37<div id="NPG_res_div"> 38<div id="NPG_gcc"> 39<div id="NPG_priority_queue_text_modify_down_timing_test"> 40<div id="NPG_pq"> 41<div id="NPG_Native_and__tt_pb_ds_455tt__priority_queue__tt_modify_455tt__timing_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NPG" id="NPG"><img src="priority_queue_text_modify_down_timing_test_gcc.png" alt="no image" /></a></h6>NPG: Native and <tt>pb ds</tt> priority queue <tt>modify</tt> timing test - <a href="pq_performance_tests.html#gcc">g++</a><p>In the above figure, the names in the legends have the following meaning:</p> 42<ol> 43<li> 44n_pq_deque- 45<tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li> 46<li> 47n_pq_vector- 48<tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li> 49<li> 50binary_heap- 51<a href="priority_queue.html"><tt>priority_queue</tt></a> 52 with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a> 53</li> 54<li> 55thin_heap- 56<a href="priority_queue.html"><tt>priority_queue</tt></a> 57 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> 58</li> 59<li> 60rc_binomial_heap- 61<a href="priority_queue.html"><tt>priority_queue</tt></a> 62 with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a> 63</li> 64<li> 65binomial_heap- 66<a href="priority_queue.html"><tt>priority_queue</tt></a> 67 with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a> 68</li> 69<li> 70pairing_heap- 71<a href="priority_queue.html"><tt>priority_queue</tt></a> 72 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> 73</li> 74</ol> 75</div><div style="width: 100%; height: 20px"></div></div> 76</div> 77</div> 78</div> 79</div> 80<div id="NPM_res_div"> 81<div id="NPM_msvc"> 82<div id="NPM_priority_queue_text_modify_down_timing_test"> 83<div id="NPM_pq"> 84<div id="NPM_Native_and__tt_pb_ds_455tt__priority_queue__tt_modify_455tt__timing_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NPM" id="NPM"><img src="priority_queue_text_modify_down_timing_test_msvc.png" alt="no image" /></a></h6>NPM: Native and <tt>pb ds</tt> priority queue <tt>modify</tt> timing test - <a href="pq_performance_tests.html#msvc">msvc++</a><p>In the above figure, the names in the legends have the following meaning:</p> 85<ol> 86<li> 87n_pq_deque- 88<tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li> 89<li> 90n_pq_vector- 91<tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li> 92<li> 93binary_heap- 94<a href="priority_queue.html"><tt>priority_queue</tt></a> 95 with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a> 96</li> 97<li> 98thin_heap- 99<a href="priority_queue.html"><tt>priority_queue</tt></a> 100 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> 101</li> 102<li> 103rc_binomial_heap- 104<a href="priority_queue.html"><tt>priority_queue</tt></a> 105 with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a> 106</li> 107<li> 108binomial_heap- 109<a href="priority_queue.html"><tt>priority_queue</tt></a> 110 with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a> 111</li> 112<li> 113pairing_heap- 114<a href="priority_queue.html"><tt>priority_queue</tt></a> 115 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> 116</li> 117</ol> 118</div><div style="width: 100%; height: 20px"></div></div> 119</div> 120</div> 121</div> 122</div> 123<div id="NPL_res_div"> 124<div id="NPL_local"> 125<div id="NPL_priority_queue_text_modify_down_timing_test"> 126<div id="NPL_pq"> 127<div id="NPL_Native_and__tt_pb_ds_455tt__priority_queue__tt_modify_455tt__timing_test"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NPL" id= "NPL"><img src="priority_queue_text_modify_down_timing_test_local.png" alt="no image" /></a></h6>NPL: Native and <tt>pb ds</tt> priority queue <tt>modify</tt> timing test - <a href = "pq_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div> 128</div> 129</div> 130</div> 131</div> 132<div id="NRTG_res_div"> 133<div id="NRTG_gcc"> 134<div id="NRTG_priority_queue_text_modify_down_timing_test_pairing_thin"> 135<div id="NRTG_pq"> 136<div id="NRTG_Pairing_and_thin__priority_queue__tt_modify_455tt__timing_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NRTG" id="NRTG"><img src="priority_queue_text_modify_down_timing_test_pairing_thin_gcc.png" alt="no image" /></a></h6>NRTG: Pairing and thin priority queue <tt>modify</tt> timing test - <a href="pq_performance_tests.html#gcc">g++</a><p>In the above figure, the names in the legends have the following meaning:</p> 137<ol> 138<li> 139thin_heap- 140<a href="priority_queue.html"><tt>priority_queue</tt></a> 141 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> 142</li> 143<li> 144pairing_heap- 145<a href="priority_queue.html"><tt>priority_queue</tt></a> 146 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> 147</li> 148</ol> 149</div><div style="width: 100%; height: 20px"></div></div> 150</div> 151</div> 152</div> 153</div> 154<div id="NRTM_res_div"> 155<div id="NRTM_msvc"> 156<div id="NRTM_priority_queue_text_modify_down_timing_test_pairing_thin"> 157<div id="NRTM_pq"> 158<div id="NRTM_Pairing_and_thin__priority_queue__tt_modify_455tt__timing_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NRTM" id="NRTM"><img src="priority_queue_text_modify_down_timing_test_pairing_thin_msvc.png" alt="no image" /></a></h6>NRTM: Pairing and thin priority queue <tt>modify</tt> timing test - <a href="pq_performance_tests.html#msvc">msvc++</a><p>In the above figure, the names in the legends have the following meaning:</p> 159<ol> 160<li> 161thin_heap- 162<a href="priority_queue.html"><tt>priority_queue</tt></a> 163 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> 164</li> 165<li> 166pairing_heap- 167<a href="priority_queue.html"><tt>priority_queue</tt></a> 168 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> 169</li> 170</ol> 171</div><div style="width: 100%; height: 20px"></div></div> 172</div> 173</div> 174</div> 175</div> 176<div id="NRTL_res_div"> 177<div id="NRTL_local"> 178<div id="NRTL_priority_queue_text_modify_down_timing_test_pairing_thin"> 179<div id="NRTL_pq"> 180<div id="NRTL_Pairing_and_thin__priority_queue__tt_modify_455tt__timing_test"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NRTL" id= "NRTL"><img src="priority_queue_text_modify_down_timing_test_pairing_thin_local.png" alt="no image" /></a></h6>NRTL: Pairing and thin priority queue <tt>modify</tt> timing test - <a href = "pq_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div> 181</div> 182</div> 183</div> 184</div> 185<h2><a name="observations" id="observations">Observations</a></h2> 186<p>Most points in these results are similar to <a href="priority_queue_text_modify_up_timing_test.html">Priority Queue 187 Text <tt>modify</tt> Timing Test - I</a>.</p> 188<p>It is interesting to note, however, that as opposed to that 189 test, a thin heap (<a href="priority_queue.html"><tt>priority_queue</tt></a> with 190 <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a>) is 191 outperformed by a pairing heap (<a href="priority_queue.html"><tt>priority_queue</tt></a> with 192 <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a>). 193 In this case, both heaps essentially perform an <tt>erase</tt> 194 operation followed by a <tt>push</tt> operation. As the other 195 tests show, a pairing heap is usually far more efficient than a 196 thin heap, so this is not surprising.</p> 197<p>Most algorithms that involve priority queues increase values 198 (in the sense of the priority queue's comparison functor), and 199 so <a href="priority_queue_text_modify_up_timing_test.html">Priority Queue 200 Text <tt>modify</tt> Timing Test - I</a> is more interesting 201 than this test.</p> 202</div> 203</body> 204</html> 205