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| <title>Priority Queue Text Join Timing Test</title> |
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| <h1>Priority Queue Text <tt>join</tt> Timing Test</h1> |
| <h2><a name="description" id="description">Description</a></h2> |
| <p>This test inserts a number of values with keys from an |
| arbitrary text ([ <a href="references.html#wickland96thirty">wickland96thirty</a> ]) into |
| two containers, then merges the containers. It uses |
| <tt>join</tt> for <tt>pb_ds</tt>'s priority queues; for the |
| STL's priority queues, it successively pops values from one |
| container and pushes them into the other. The test measures the |
| average time as a function of the number of values.</p> |
| <p>(The test was executed with <a href="../../../../testsuite/performance/ext/pb_ds/priority_queue_text_join_timing.cc"><tt>priority_queue_text_join_timing_test</tt></a> |
| thirty_years_among_the_dead_preproc.txt 200 200 2100)</p> |
| <h2><a name="purpose" id="purpose">Purpose</a></h2> |
| <p>The test checks the effect of different underlying |
| data structures (see <a href="pq_design.html#pq_imp">Design::Priority |
| Queues::Implementations</a>).</p> |
| <h2><a name="results" id="results">Results</a></h2> |
| <p>Figures <a href="#NPG">NPG</a>, <a href="#NPM">NPM</a>, and |
| <a href="#NPL">NPL</a> show the results for the native priority |
| 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 <a href="pq_performance_tests.html#local"><u>local</u></a>, |
| respectively.</p> |
| <div id="NPG_res_div"> |
| <div id="NPG_gcc"> |
| <div id="NPG_priority_queue_text_join_timing_test"> |
| <div id="NPG_pq"> |
| <div id="NPG_Native_tree_and__tt_pb_ds_455tt__priority_queue__tt_push_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_join_timing_test_gcc.png" alt="no image" /></a></h6>NPG: Native tree and <tt>pb ds</tt> priority queue <tt>push</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> |
| <ol> |
| <li> |
| n_pq_deque- |
| <tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li> |
| <li> |
| n_pq_vector- |
| <tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li> |
| <li> |
| binary_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a> |
| </li> |
| <li> |
| thin_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> |
| </li> |
| <li> |
| rc_binomial_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a> |
| </li> |
| <li> |
| pairing_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> |
| </li> |
| <li> |
| binomial_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a> |
| </li> |
| </ol> |
| </div><div style="width: 100%; height: 20px"></div></div> |
| </div> |
| </div> |
| </div> |
| </div> |
| <div id="NPM_res_div"> |
| <div id="NPM_msvc"> |
| <div id="NPM_priority_queue_text_join_timing_test"> |
| <div id="NPM_pq"> |
| <div id="NPM_Native_tree_and__tt_pb_ds_455tt__priority_queue__tt_push_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_join_timing_test_msvc.png" alt="no image" /></a></h6>NPM: Native tree and <tt>pb ds</tt> priority queue <tt>push</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> |
| <ol> |
| <li> |
| n_pq_deque- |
| <tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li> |
| <li> |
| n_pq_vector- |
| <tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li> |
| <li> |
| binary_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a> |
| </li> |
| <li> |
| thin_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a> |
| </li> |
| <li> |
| rc_binomial_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a> |
| </li> |
| <li> |
| pairing_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a> |
| </li> |
| <li> |
| binomial_heap- |
| <a href="priority_queue.html"><tt>priority_queue</tt></a> |
| with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a> |
| </li> |
| </ol> |
| </div><div style="width: 100%; height: 20px"></div></div> |
| </div> |
| </div> |
| </div> |
| </div> |
| <div id="NPL_res_div"> |
| <div id="NPL_local"> |
| <div id="NPL_priority_queue_text_join_timing_test"> |
| <div id="NPL_pq"> |
| <div id="NPL_Native_tree_and__tt_pb_ds_455tt__priority_queue__tt_push_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_join_timing_test_local.png" alt="no image" /></a></h6>NPL: Native tree and <tt>pb ds</tt> priority queue <tt>push</tt> timing test - <a href = "pq_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div> |
| </div> |
| </div> |
| </div> |
| </div> |
| <h2><a name="observations" id="observations">Observations</a></h2> |
| <p>In this test the node-based heaps perform <tt>join</tt> in |
| either logarithmic or constant time. The binary heap requires |
| linear time, since the well-known heapify algorithm [<a href="references.html#clrs2001">clrs2001</a>] is linear.</p> |
| <p>It would be possible to apply the heapify algorithm to the |
| STL containers, if they would support iteration (which they |
| don't). Barring iterators, it is still somehow possible to |
| perform linear-time merge on a <tt>std::vector</tt>-based STL |
| priority queue, using <tt>top()</tt> and <tt>size()</tt> (since |
| they are enough to expose the underlying array), but this is |
| impossible for a <tt>std::deque</tt>-based STL priority queue. |
| Without heapify, the cost is super-linear.</p> |
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