PageRenderTime 27ms CodeModel.GetById 0ms RepoModel.GetById 0ms app.codeStats 0ms

/libstdc++-v3/doc/html/ext/pb_ds/hash_random_int_find_find_timing_test.html

https://bitbucket.org/pizzafactory/pf-gcc
HTML | 247 lines | 246 code | 1 blank | 0 comment | 0 complexity | 35f620ad885bde3ec87ee6c3bb8ac7db MD5 | raw file
    

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    2. 

  2.     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    3. 

  3. 

  4. <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    5. 

  5. <head>
    6. 

  6. <meta name="generator" content="HTML Tidy for Linux/x86 (vers 12 April 2005), see www.w3.org" />
    7. 

  7. <title>Hash Random Int Find Timing Test</title>
    8. 

  8. <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
    9. 

  9. </head>
    10. 

  10. <body>
    11. 

  11. <div id="page">
    12. 

  12. <h1>Hash-Based Random-Integer <tt>find</tt> Find Timing
    13. 

  13.     Test</h1>
    14. 

  14. <h2><a name="description" id="description">Description</a></h2>
    15. 

  15. <p>This test inserts a number of values with uniform i.i.d.
    16. 

  16.     integer keys into a container, then performs a series of finds
    17. 

  17.     using <tt>find</tt>. It measures the average time
    18. 

  18.     for<tt>find</tt> as a function of the number of values
    19. 

  19.     inserted.</p>
    20. 

  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. 

  21.     200 200 2100)</p>
    22. 

  22. <h2><a name="purpose" id="purpose">Purpose</a></h2>
    23. 

  23. <p>The test checks the effect of different underlying
    24. 

  24.     hash-tables (see <a href="hash_based_containers.html">Design::Associative
    25. 

  25.     Containers::Associative Containers::Hash-Based Containers</a>),
    26. 

  26.     range-hashing functions, and trigger policies (see <a href="hash_based_containers.html#hash_policies">Design::Associative
    27. 

  27.     Containers::Hash-Based Containers::Hash Policies</a> and
    28. 

  28.     <a href="hash_based_containers.html#resize_policies">Design::Associative
    29. 

  29.     Containers::Hash-Based Containers::Resize Policies</a>).</p>
    30. 

  30. <h2><a name="results" id="results">Results</a></h2>
    31. 

  31. <p>Figures <a href="#NCCG">NCCG</a>, <a href="#NCCM">NCCM</a>,
    32. 

  32.     and <a href="#NCCL">NCCL</a> show the results for the native
    33. 

  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. 

  34.     <a href="assoc_performance_tests.html#local"><u>local</u></a>,
    35. 

  35.     respectively; Figures <a href="#NGPG">NGPG</a>, <a href="#NGPM">NGPM</a>, and <a href="#NGPL">NGPL</a> show the results
    36. 

  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. 

  37.     <a href="assoc_performance_tests.html#local"><u>local</u></a>
    38. 

  38.     respectively.</p>
    39. 

  39. <div id="NCCG_res_div">
    40. 

  40. <div id="NCCG_gcc">
    41. 

  41. <div id="NCCG_cc_hash_random_int_find_timing_test">
    42. 

  42. <div id="NCCG_assoc">
    43. 

  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. 

  44. <ol>
    45. 

  45. <li>
    46. 

  46. n_hash_map_ncah-
    47. 

  47. <tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li>
    48. 

  48. <li>
    49. 

  49. cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map-
    50. 

  50. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    51. 

  51. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    52. 

  52. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    53. 

  53.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    54. 

  54. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    55. 

  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. 

  56. <li>
    57. 

  57. cc_hash_mod_prime_nea_lc_1div8_1div2_nsth_map-
    58. 

  58. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    59. 

  59. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    60. 

  60. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    61. 

  61.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    62. 

  62. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    63. 

  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. 

  64. <li>
    65. 

  65. cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map-
    66. 

  66. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    67. 

  67. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    68. 

  68. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    69. 

  69.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    70. 

  70. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    71. 

  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. 

  72. <li>
    73. 

  73. cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map-
    74. 

  74. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    75. 

  75. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    76. 

  76. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    77. 

  77.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    78. 

  78. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    79. 

  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. 

  80. </ol>
    81. 

  81. </div><div style="width: 100%; height: 20px"></div></div>
    82. 

  82. </div>
    83. 

  83. </div>
    84. 

  84. </div>
    85. 

  85. </div>
    86. 

  86. <div id="NCCM_res_div">
    87. 

  87. <div id="NCCM_msvc">
    88. 

  88. <div id="NCCM_cc_hash_random_int_find_timing_test">
    89. 

  89. <div id="NCCM_assoc">
    90. 

  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. 

  91. <ol>
    92. 

  92. <li>
    93. 

  93. cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map-
    94. 

  94. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    95. 

  95. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    96. 

  96. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    97. 

  97.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    98. 

  98. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    99. 

  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. 

  100. <li>
    101. 

  101. cc_hash_mod_prime_nea_lc_1div8_1div2_nsth_map-
    102. 

  102. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    103. 

  103. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    104. 

  104. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    105. 

  105.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    106. 

  106. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    107. 

  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. 

  108. <li>
    109. 

  109. n_hash_map_ncah-
    110. 

  110. <tt>stdext::hash_map</tt></li>
    111. 

  111. <li>
    112. 

  112. cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map-
    113. 

  113. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    114. 

  114. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    115. 

  115. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    116. 

  116.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    117. 

  117. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    118. 

  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. 

  119. <li>
    120. 

  120. cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map-
    121. 

  121. <a href="cc_hash_table.html"><tt>cc_hash_table</tt></a>
    122. 

  122. with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    123. 

  123. , and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    124. 

  124.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    125. 

  125. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    126. 

  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. 

  127. </ol>
    128. 

  128. </div><div style="width: 100%; height: 20px"></div></div>
    129. 

  129. </div>
    130. 

  130. </div>
    131. 

  131. </div>
    132. 

  132. </div>
    133. 

  133. <div id="NCCL_res_div">
    134. 

  134. <div id="NCCL_local">
    135. 

  135. <div id="NCCL_cc_hash_random_int_find_timing_test">
    136. 

  136. <div id="NCCL_assoc">
    137. 

  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. 

  138. </div>
    139. 

  139. </div>
    140. 

  140. </div>
    141. 

  141. </div>
    142. 

  142. <div id="NGPG_res_div">
    143. 

  143. <div id="NGPG_gcc">
    144. 

  144. <div id="NGPG_gp_hash_random_int_find_timing_test">
    145. 

  145. <div id="NGPG_assoc">
    146. 

  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. 

  147. <ol>
    148. 

  148. <li>
    149. 

  149. gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map-
    150. 

  150. <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
    151. 

  151.  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    152. 

  152. , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    153. 

  153.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    154. 

  154. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    155. 

  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. 

  156. </li>
    157. 

  157. <li>
    158. 

  158. n_hash_map_ncah-
    159. 

  159. <tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li>
    160. 

  160. <li>
    161. 

  161. gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_map-
    162. 

  162. <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
    163. 

  163.  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    164. 

  164. , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    165. 

  165.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    166. 

  166. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    167. 

  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. 

  168. </li>
    169. 

  169. </ol>
    170. 

  170. </div><div style="width: 100%; height: 20px"></div></div>
    171. 

  171. </div>
    172. 

  172. </div>
    173. 

  173. </div>
    174. 

  174. </div>
    175. 

  175. <div id="NGPM_res_div">
    176. 

  176. <div id="NGPM_msvc">
    177. 

  177. <div id="NGPM_gp_hash_random_int_find_timing_test">
    178. 

  178. <div id="NGPM_assoc">
    179. 

  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. 

  180. <ol>
    181. 

  181. <li>
    182. 

  182. gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map-
    183. 

  183. <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
    184. 

  184.  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a>
    185. 

  185. , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    186. 

  186.  with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a>
    187. 

  187. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    188. 

  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. 

  189. </li>
    190. 

  190. <li>
    191. 

  191. n_hash_map_ncah-
    192. 

  192. <tt>stdext::hash_map</tt></li>
    193. 

  193. <li>
    194. 

  194. gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_map-
    195. 

  195. <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a>
    196. 

  196.  with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a>
    197. 

  197. , <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a>
    198. 

  198.  with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a>
    199. 

  199. , and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a>
    200. 

  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. 

  201. </li>
    202. 

  202. </ol>
    203. 

  203. </div><div style="width: 100%; height: 20px"></div></div>
    204. 

  204. </div>
    205. 

  205. </div>
    206. 

  206. </div>
    207. 

  207. </div>
    208. 

  208. <div id="NGPL_res_div">
    209. 

  209. <div id="NGPL_local">
    210. 

  210. <div id="NGPL_gp_hash_random_int_find_timing_test">
    211. 

  211. <div id="NGPL_assoc">
    212. 

  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. 

  213. </div>
    214. 

  214. </div>
    215. 

  215. </div>
    216. 

  216. </div>
    217. 

  217. <h2><a name="observations" id="observations">Observations</a></h2>
    218. 

  218. <p>In this setting, the choice of underlying hash-table (see
    219. 

  219.     <a href="hash_based_containers.html">Design::Associative
    220. 

  220.     Containers::Hash-Based Containers</a> ) affects performance
    221. 

  221.     most, then the range-hashing scheme (See <a href="hash_based_containers.html#hash_policies">Design::Associative
    222. 

  222.     Containers::Hash-Based Containers::Hash Policies</a> ), and,
    223. 

  223.     only finally, other policies.</p>
    224. 

  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. 

  225.     probing containers are less efficient than the
    226. 

  226.     collision-chaining containers (both
    227. 

  227.     <tt>std::tr1::unordered_map</tt> and <tt>stdext::hash_map</tt>
    228. 

  228.     use collision-chaining) in this case.</p>
    229. 

  229. <p>( <a href="hash_random_int_subscript_insert_timing_test.html">Hash-Based
    230. 

  230.     Random-Integer Subscript Insert Timing Test</a> shows a
    231. 

  231.     different case, where the situation is reversed; <a href="assoc_performance_tests.html#hash_based_types">Observations::Hash-Based
    232. 

  232.     Container Types</a> discusses some further considerations.)</p>
    233. 

  233. <p>Within each type of hash-table, the range-hashing scheme
    234. 

  234.     affects performance more than other policies; <a href="hash_text_find_find_timing_test.html#observations">Hash-Based
    235. 

  235.     Text <tt>find</tt> Find Timing Test::Observations</a> discusses
    236. 

  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. 

  237.     <tt>std::tr1::unordered_map</tt> and <tt>stdext::hash_map</tt>
    238. 

  238.     are hard-wired currently to mod-based and mask-based schemes,
    239. 

  239.     respectively.</p>
    240. 

  240. <p><a href="assoc_performance_tests.html#hash_based_types">Observations::Hash-Based
    241. 

  241.     Container Types</a> summarizes some observations on hash-based
    242. 

  242.     containers; <a href="assoc_performance_tests.html#hash_based_policies">Observations::Hash-Based
    243. 

  243.     Containers' Policies</a> summarizes some observations on
    244. 

  244.     hash-based containers' policies.</p>
    245. 

  245. </div>
    246. 

  246. </body>
    247. 

  247. </html>
    248. 

  248.