l4/pkg/libstdc++-v3/contrib/libstdc++-v3-4.4/doc/html/ext/pb_ds/hash_random_int_find_find_timing_test.html

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  12 <h1>Hash-Based Random-Integer <tt>find</tt> Find Timing
  13     Test</h1>
  14 <h2><a name="description" id="description">Description</a></h2>
  15 <p>This test inserts a number of values with uniform i.i.d.
  16     integer keys into a container, then performs a series of finds
  17     using <tt>find</tt>. It measures the average time
  18     for<tt>find</tt> as a function of the number of values
  19     inserted.</p>
  20 <p>(The test was executed with <a href="http://gcc.gnu.org/viewcvs/*checkout*/trunk/libstdc%2B%2B-v3/testsuite/performance/ext/pb_ds/random_int_find_timing.cc"><tt>random_int_find_timing_test</tt></a>
  21     200 200 2100)</p>
  22 <h2><a name="purpose" id="purpose">Purpose</a></h2>
  23 <p>The test checks the effect of different underlying
  24     hash-tables (see <a href="hash_based_containers.html">Design::Associative
  25     Containers::Associative Containers::Hash-Based Containers</a>),
  26     range-hashing functions, and trigger policies (see <a href="hash_based_containers.html#hash_policies">Design::Associative
  27     Containers::Hash-Based Containers::Hash Policies</a> and
  28     <a href="hash_based_containers.html#resize_policies">Design::Associative
  29     Containers::Hash-Based Containers::Resize Policies</a>).</p>
  30 <h2><a name="results" id="results">Results</a></h2>
  31 <p>Figures <a href="#NCCG">NCCG</a>, <a href="#NCCM">NCCM</a>,
  32     and <a href="#NCCL">NCCL</a> show the results for the native
  33     and collision-chaining types in <a href="assoc_performance_tests.html#gcc"><u>g++</u></a>, <a href="assoc_performance_tests.html#msvc"><u>MSVC++</u></a>, and
  34     <a href="assoc_performance_tests.html#local"><u>local</u></a>,
  35     respectively; Figures <a href="#NGPG">NGPG</a>, <a href="#NGPM">NGPM</a>, and <a href="#NGPL">NGPL</a> show the results
  36     for the native and probing types in <a href="assoc_performance_tests.html#gcc"><u>g++</u></a>, <a href="assoc_performance_tests.html#msvc"><u>MSVC++</u></a>, and
  37     <a href="assoc_performance_tests.html#local"><u>local</u></a>
  38     respectively.</p>
  39 <div id="NCCG_res_div">
  40 <div id="NCCG_gcc">
  41 <div id="NCCG_cc_hash_random_int_find_timing_test">
  42 <div id="NCCG_assoc">
  43 <div id="NCCG_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCG" id="NCCG"><img src="cc_hash_random_int_find_timing_test_gcc.png" alt="no image" /></a></h6>NCCG: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#gcc">g++</a><p>In the above figure, the names in the legends have the following meaning:</p>
  44 <ol>
  45 <li>
  46 n_hash_map_ncah-
  47 <tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li>
  48 <li>
  49 cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map-
  50 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
  51 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
  52 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
  53  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
  54 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
  55  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/1</i></li>
  56 <li>
  57 cc_hash_mod_prime_nea_lc_1div8_1div2_nsth_map-
  58 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
  59 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
  60 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
  61  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
  62 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
  63  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i></li>
  64 <li>
  65 cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map-
  66 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
  67 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
  68 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
  69  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
  70 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
  71  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/1</i></li>
  72 <li>
  73 cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map-
  74 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
  75 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
  76 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
  77  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
  78 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
  79  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i></li>
  80 </ol>
  81 </div><div style="width: 100%; height: 20px"></div></div>
  82 </div>
  83 </div>
  84 </div>
  85 </div>
  86 <div id="NCCM_res_div">
  87 <div id="NCCM_msvc">
  88 <div id="NCCM_cc_hash_random_int_find_timing_test">
  89 <div id="NCCM_assoc">
  90 <div id="NCCM_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCM" id="NCCM"><img src="cc_hash_random_int_find_timing_test_msvc.png" alt="no image" /></a></h6>NCCM: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#msvc">msvc++</a><p>In the above figure, the names in the legends have the following meaning:</p>
  91 <ol>
  92 <li>
  93 cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map-
  94 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
  95 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
  96 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
  97  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
  98 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
  99  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/1</i></li>
 100 <li>
 101 cc_hash_mod_prime_nea_lc_1div8_1div2_nsth_map-
 102 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
 103 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
 104 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 105  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
 106 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 107  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i></li>
 108 <li>
 109 n_hash_map_ncah-
 110 <tt>stdext::hash_map</tt></li>
 111 <li>
 112 cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map-
 113 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
 114 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
 115 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 116  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
 117 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 118  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/1</i></li>
 119 <li>
 120 cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map-
 121 <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
 122 with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
 123 , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 124  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
 125 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 126  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i></li>
 127 </ol>
 128 </div><div style="width: 100%; height: 20px"></div></div>
 129 </div>
 130 </div>
 131 </div>
 132 </div>
 133 <div id="NCCL_res_div">
 134 <div id="NCCL_local">
 135 <div id="NCCL_cc_hash_random_int_find_timing_test">
 136 <div id="NCCL_assoc">
 137 <div id="NCCL_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCL" id= "NCCL"><img src="cc_hash_random_int_find_timing_test_local.png" alt="no image" /></a></h6>NCCL: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href = "assoc_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div>
 138 </div>
 139 </div>
 140 </div>
 141 </div>
 142 <div id="NGPG_res_div">
 143 <div id="NGPG_gcc">
 144 <div id="NGPG_gp_hash_random_int_find_timing_test">
 145 <div id="NGPG_assoc">
 146 <div id="NGPG_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NGPG" id="NGPG"><img src="gp_hash_random_int_find_timing_test_gcc.png" alt="no image" /></a></h6>NGPG: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#gcc">g++</a><p>In the above figure, the names in the legends have the following meaning:</p>
 147 <ol>
 148 <li>
 149 gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map-
 150 <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
 151  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
 152 , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 153  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
 154 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 155  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i>, and <tt>Probe_Fn</tt> = <a href="quadratic_probe_fn.html"><tt>quadratic_probe_fn</tt></a>
 156 </li>
 157 <li>
 158 n_hash_map_ncah-
 159 <tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li>
 160 <li>
 161 gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_map-
 162 <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
 163  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
 164 , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 165  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
 166 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 167  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i>, and <tt>Probe_Fn</tt> = <a href="linear_probe_fn.html"><tt>linear_probe_fn</tt></a>
 168 </li>
 169 </ol>
 170 </div><div style="width: 100%; height: 20px"></div></div>
 171 </div>
 172 </div>
 173 </div>
 174 </div>
 175 <div id="NGPM_res_div">
 176 <div id="NGPM_msvc">
 177 <div id="NGPM_gp_hash_random_int_find_timing_test">
 178 <div id="NGPM_assoc">
 179 <div id="NGPM_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NGPM" id="NGPM"><img src="gp_hash_random_int_find_timing_test_msvc.png" alt="no image" /></a></h6>NGPM: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#msvc">msvc++</a><p>In the above figure, the names in the legends have the following meaning:</p>
 180 <ol>
 181 <li>
 182 gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map-
 183 <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
 184  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
 185 , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 186  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
 187 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 188  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i>, and <tt>Probe_Fn</tt> = <a href="quadratic_probe_fn.html"><tt>quadratic_probe_fn</tt></a>
 189 </li>
 190 <li>
 191 n_hash_map_ncah-
 192 <tt>stdext::hash_map</tt></li>
 193 <li>
 194 gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_map-
 195 <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
 196  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
 197 , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
 198  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
 199 , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
 200  with <i>&alpha;<sub>min</sub></i> = <i>1/8</i> and <i>&alpha;<sub>max</sub></i> = <i>1/2</i>, and <tt>Probe_Fn</tt> = <a href="linear_probe_fn.html"><tt>linear_probe_fn</tt></a>
 201 </li>
 202 </ol>
 203 </div><div style="width: 100%; height: 20px"></div></div>
 204 </div>
 205 </div>
 206 </div>
 207 </div>
 208 <div id="NGPL_res_div">
 209 <div id="NGPL_local">
 210 <div id="NGPL_gp_hash_random_int_find_timing_test">
 211 <div id="NGPL_assoc">
 212 <div id="NGPL_Native_and_collision-chaining_hash_random_int_find_timing_test_using__tt_find_455tt_"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NGPL" id= "NGPL"><img src="gp_hash_random_int_find_timing_test_local.png" alt="no image" /></a></h6>NGPL: Native and collision-chaining hash random int find timing test using <tt>find</tt> - <a href = "assoc_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div>
 213 </div>
 214 </div>
 215 </div>
 216 </div>
 217 <h2><a name="observations" id="observations">Observations</a></h2>
 218 <p>In this setting, the choice of underlying hash-table (see
 219     <a href="hash_based_containers.html">Design::Associative
 220     Containers::Hash-Based Containers</a> ) affects performance
 221     most, then the range-hashing scheme (See <a href="hash_based_containers.html#hash_policies">Design::Associative
 222     Containers::Hash-Based Containers::Hash Policies</a> ), and,
 223     only finally, other policies.</p>
 224 <p>When comparing Figures <a href="#NCCG">NCCG</a> and <a href="#NCCM">NCCM</a> to <a href="#NGPG">NGPG</a> and <a href="#NGPM">NGPM</a> , respectively, it is apparent that the
 225     probing containers are less efficient than the
 226     collision-chaining containers (both
 227     <tt>std::tr1::unordered_map</tt> and <tt>stdext::hash_map</tt>
 228     use collision-chaining) in this case.</p>
 229 <p>( <a href="hash_random_int_subscript_insert_timing_test.html">Hash-Based
 230     Random-Integer Subscript Insert Timing Test</a> shows a
 231     different case, where the situation is reversed; <a href="assoc_performance_tests.html#hash_based_types">Observations::Hash-Based
 232     Container Types</a> discusses some further considerations.)</p>
 233 <p>Within each type of hash-table, the range-hashing scheme
 234     affects performance more than other policies; <a href="hash_text_find_find_timing_test.html#observations">Hash-Based
 235     Text <tt>find</tt> Find Timing Test::Observations</a> discusses
 236     this. In Figures <a href="#NCCG">NCCG</a> , <a href="#NCCM">NCCM</a> , <a href="#NGPG">NGPG</a> , and <a href="#NGPM">NGPM</a> , it should be noted that
 237     <tt>std::tr1::unordered_map</tt> and <tt>stdext::hash_map</tt>
 238     are hard-wired currently to mod-based and mask-based schemes,
 239     respectively.</p>
 240 <p><a href="assoc_performance_tests.html#hash_based_types">Observations::Hash-Based
 241     Container Types</a> summarizes some observations on hash-based
 242     containers; <a href="assoc_performance_tests.html#hash_based_policies">Observations::Hash-Based
 243     Containers' Policies</a> summarizes some observations on
 244     hash-based containers' policies.</p>
 245 </div>
 246 </body>
 247 </html>