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7<title>Priority Queue Text Pop Memory Use Test</title>
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12<h1>Priority Queue Text <tt>pop</tt> Memory Use Test</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    a container, then pops them until only one is left in the
17    container. It measures the memory use as a function of the
18    number of values pushed to the container.</p>
19<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_pop_mem_usage.cc"><tt>priority_queue_text_pop_mem_usage_test</tt></a>
20    thirty_years_among_the_dead_preproc.txt 200 200 2100)</p>
21<h2><a name="purpose" id="purpose">Purpose</a></h2>
22<p>The test checks the effect of different underlying
23    data structures (see <a href="pq_design.html#pq_imp">Design::Priority
24    Queues::Implementations</a>).</p>
25<h2><a name="results" id="results">Results</a></h2>
26<p>Figures <a href="#NPG">NPG</a>, <a href="#NPM">NPM</a>, and
27    <a href="#NPL">NPL</a> show the results for the native priority
28    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
29    <a href="pq_performance_tests.html#local"><u>local</u></a>,
30    respectively.</p>
31<div id="NPG_res_div">
32<div id="NPG_gcc">
33<div id="NPG_priority_queue_text_pop_mem_usage_test">
34<div id="NPG_pq">
35<div id="NPG_Native_and__tt_pb_ds_455tt__priority_queue__tt_pop_455tt__memory-use_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_pop_mem_usage_test_gcc.png" alt="no image" /></a></h6>NPG: Native and <tt>pb ds</tt> priority queue <tt>pop</tt> memory-use 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>
36<ol>
37<li>
38n_pq_vector-
39<tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li>
40<li>
41n_pq_deque-
42<tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li>
43<li>
44binary_heap-
45<a href="priority_queue.html"><tt>priority_queue</tt></a>
46 with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a>
47</li>
48<li>
49thin_heap-
50<a href="priority_queue.html"><tt>priority_queue</tt></a>
51 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a>
52</li>
53<li>
54binomial_heap-
55<a href="priority_queue.html"><tt>priority_queue</tt></a>
56 with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a>
57</li>
58<li>
59rc_binomial_heap-
60<a href="priority_queue.html"><tt>priority_queue</tt></a>
61 with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a>
62</li>
63<li>
64pairing_heap-
65<a href="priority_queue.html"><tt>priority_queue</tt></a>
66 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a>
67</li>
68</ol>
69</div><div style="width: 100%; height: 20px"></div></div>
70</div>
71</div>
72</div>
73</div>
74<div id="NPM_res_div">
75<div id="NPM_msvc">
76<div id="NPM_priority_queue_text_pop_mem_usage_test">
77<div id="NPM_pq">
78<div id="NPM_Native_and__tt_pb_ds_455tt__priority_queue__tt_pop_455tt__memory-use_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_pop_mem_usage_test_msvc.png" alt="no image" /></a></h6>NPM: Native and <tt>pb ds</tt> priority queue <tt>pop</tt> memory-use 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>
79<ol>
80<li>
81n_pq_vector-
82<tt>std::priority_queue</tt> adapting <tt>std::vector</tt></li>
83<li>
84n_pq_deque-
85<tt>std::priority_queue</tt> adapting <tt>std::deque</tt></li>
86<li>
87binary_heap-
88<a href="priority_queue.html"><tt>priority_queue</tt></a>
89 with <tt>Tag</tt> = <a href="binary_heap_tag.html"><tt>binary_heap_tag</tt></a>
90</li>
91<li>
92thin_heap-
93<a href="priority_queue.html"><tt>priority_queue</tt></a>
94 with <tt>Tag</tt> = <a href="thin_heap_tag.html"><tt>thin_heap_tag</tt></a>
95</li>
96<li>
97binomial_heap-
98<a href="priority_queue.html"><tt>priority_queue</tt></a>
99 with <tt>Tag</tt> = <a href="binomial_heap_tag.html"><tt>binomial_heap_tag</tt></a>
100</li>
101<li>
102rc_binomial_heap-
103<a href="priority_queue.html"><tt>priority_queue</tt></a>
104 with <tt>Tag</tt> = <a href="rc_binomial_heap_tag.html"><tt>rc_binomial_heap_tag</tt></a>
105</li>
106<li>
107pairing_heap-
108<a href="priority_queue.html"><tt>priority_queue</tt></a>
109 with <tt>Tag</tt> = <a href="pairing_heap_tag.html"><tt>pairing_heap_tag</tt></a>
110</li>
111</ol>
112</div><div style="width: 100%; height: 20px"></div></div>
113</div>
114</div>
115</div>
116</div>
117<div id="NPL_res_div">
118<div id="NPL_local">
119<div id="NPL_priority_queue_text_pop_mem_usage_test">
120<div id="NPL_pq">
121<div id="NPL_Native_and__tt_pb_ds_455tt__priority_queue__tt_pop_455tt__memory-use_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_pop_mem_usage_test_local.png" alt="no image" /></a></h6>NPL: Native and <tt>pb ds</tt> priority queue <tt>pop</tt> memory-use test - <a href = "pq_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div>
122</div>
123</div>
124</div>
125</div>
126<h2><a name="observations" id="observations">Observations</a></h2>
127<p>The priority queue implementations (excluding the STL's) use
128    memory proportionally to the number of values they hold:
129    node-based implementations (<i>e.g.</i>, a pairing heap) do so
130    naturally; <tt>pb_ds</tt>'s binary heap de-allocates memory when
131    a certain lower threshold is exceeded.</p>
132<p>Note from <a href="priority_queue_text_push_pop_timing_test.html">Priority Queue
133    Text <tt>push</tt> and <tt>pop</tt> Timing Test</a> and
134    <a href="priority_queue_random_int_push_pop_timing_test.html">Priority
135    Queue Random Integer <tt>push</tt> and <tt>pop</tt> Timing
136    Test</a> that this does not impede performance compared to the
137    STL's priority queues.</p>
138<p>(See <a href="hash_random_int_erase_mem_usage_test.html">Hash-Based Erase
139    Memory Use Test</a> for a similar phenomenon regarding priority
140    queues.)</p>
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