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diff --git a/gcc-4.4.3/libstdc++-v3/doc/html/ext/pb_ds/hash_zlob_random_int_find_find_timing_test.html b/gcc-4.4.3/libstdc++-v3/doc/html/ext/pb_ds/hash_zlob_random_int_find_find_timing_test.html deleted file mode 100644 index bfbb3b086..000000000 --- a/gcc-4.4.3/libstdc++-v3/doc/html/ext/pb_ds/hash_zlob_random_int_find_find_timing_test.html +++ /dev/null @@ -1,163 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> - -<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> -<head> -<meta name="generator" content="HTML Tidy for Linux/x86 (vers 12 April 2005), see www.w3.org" /> -<title>Hash Skewed Distribution Memory Use Test</title> -<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> -</head> -<body> -<div id="page"> -<h1>Hash-Based Skewed-Distribution Random-Integer <tt>find</tt> - Find Timing Test</h1> -<h2><a name="description" id="description">Description</a></h2> -<p>This test inserts a number of values with a markedly - non-uniform i.i.d. integer keys into a container, then performs - a series of finds using <tt>find</tt> . It measures the average - time for <tt>find</tt> as a function of the number of values in - the containers. The keys are generated as follows. First, a - uniform integer is created; it is then shifted left 8 bits.</p> -<p>(The test was executed with <a href="http://gcc.gnu.org/viewcvs/*checkout*/trunk/libstdc%2B%2B-v3/testsuite/performance/ext/pb_ds/hash_zlob_random_int_find_timing.cc"><tt>hash_zlob_random_int_find_timing_test</tt></a> - 200 200 2100)</p> -<h2><a name="purpose" id="purpose">Purpose</a></h2> -<p>The test checks the effect of different range-hashing - functions and trigger policies (see <a href="hash_based_containers.html#hash_policies">Design::Associative - Containers::Hash-Based Containers::Hash Policies</a> and - <a href="hash_based_containers.html#resize_policies">Design::Associative - Containers::Hash-Based Containers::Resize Policies</a>).</p> -<h2><a name="results" id="results">Results</a></h2> -<p>Figures <a href="#NHG">NHG</a>, <a href="#NHM">NHM</a>, and - <a href="#NHL">NHL</a> show the results for various hash-based - associative-containers in <a href="assoc_performance_tests.html#gcc"><u>g++</u></a>, <a href="assoc_performance_tests.html#msvc"><u>MSVC++</u></a>, and - <a href="assoc_performance_tests.html#local"><u>local</u></a>, - respectively.</p> -<div id="NHG_res_div"> -<div id="NHG_gcc"> -<div id="NHG_hash_zlob_random_int_find_timing_test"> -<div id="NHG_assoc"> -<div id="NHG_Skewed-distribution_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="NHG" id="NHG"><img src="hash_zlob_random_int_find_timing_test_gcc.png" alt="no image" /></a></h6>NHG: Skewed-distribution 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> -<ol> -<li> -cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map- -<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> -with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> -, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> -<li> -gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map- -<a href="gp_hash_table.html"><tt>gp_hash_table</tt></a> - with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> -, <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<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> -</li> -<li> -n_hash_map_ncah- -<tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li> -<li> -cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map- -<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> -with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> -, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> -</ol> -</div><div style="width: 100%; height: 20px"></div></div> -</div> -</div> -</div> -</div> -<div id="NHM_res_div"> -<div id="NHM_msvc"> -<div id="NHM_hash_zlob_random_int_find_timing_test"> -<div id="NHM_assoc"> -<div id="NHM_Skewed-distribution_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="NHM" id="NHM"><img src="hash_zlob_random_int_find_timing_test_msvc.png" alt="no image" /></a></h6>NHM: Skewed-distribution 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> -<ol> -<li> -n_hash_map_ncah- -<tt>stdext::hash_map</tt></li> -<li> -cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map- -<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> -with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> -, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> -<li> -gp_hash_mod_quadp_prime_nea_lc_1div8_1div2_nsth_map- -<a href="gp_hash_table.html"><tt>gp_hash_table</tt></a> - with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> -, <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<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> -</li> -<li> -cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map- -<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> -with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> -, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> - with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> -, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> - with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> -</ol> -</div><div style="width: 100%; height: 20px"></div></div> -</div> -</div> -</div> -</div> -<div id="NHL_res_div"> -<div id="NHL_local"> -<div id="NHL_hash_zlob_random_int_find_timing_test"> -<div id="NHL_assoc"> -<div id="NHL_Skewed-distribution_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="NHL" id= "NHL"><img src="hash_zlob_random_int_find_timing_test_local.png" alt="no image" /></a></h6>NHL: Skewed-distribution 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> -</div> -</div> -</div> -</div> -<h2><a name="observations" id="observations">Observations</a></h2> -<p>In this setting, the keys' distribution is so skewed that - the unerlying hash-table type affects performance marginally. - (This is in contrast with <a href="hash_text_find_find_timing_test.html">Hash-Based Text - <tt>find</tt> Find Timing Test</a> , <a href="hash_random_int_find_find_timing_test.html">Hash-Based - Random-Integer <tt>find</tt> Find Timing Test</a> , <a href="hash_random_int_subscript_find_timing_test.html">Hash-Based - Random-Integer Subscript Find Timing Test</a> and <a href="hash_random_int_subscript_insert_timing_test.html">Hash-Based - Random-Integer Subscript Insert Timing Test</a> .)</p> -<p>The range-hashing scheme affects performance dramatically. A - mask-based range-hashing scheme effectively maps all values - into the same bucket. Access degenerates into a search within - an unordered linked-list. In Figures <a href="#NHG">NHG</a> and - <a href="#NHM">NHM</a> , it should be noted that - <tt>std::tr1::unordered_map</tt> and <tt>stdext::hash_map</tt> - are hard-wired currently to mod-based and mask-based schemes, - respectively.</p> -<p>When observing the settings of this test, it is apparent - that the keys' distribution is far from natural. One might ask - if the test is not contrived to show that, in some cases, - mod-based range hashing does better than mask-based range - hashing. This is, in fact just the case. We did not encounter a - more natural case in which mod-based range hashing is better. - In our opnion, real-life key distributions are handled better - with an appropriate hash function and a mask-based - range-hashing function. (<a href="http://gcc.gnu.org/viewcvs/*checkout*/trunk/libstdc%2B%2B-v3/testsuite/ext/pb_ds/example/hash_shift_mask.cc"><tt>shift_mask.cc</tt></a> - shows an example of handling this a-priori known skewed - distribution with a mask-based range-hashing function). If hash - performance is bad, a <i>Χ<sup>2</sup></i> test can be used - to check how to transform it into a more uniform - distribution.</p> -<p>For this reason, <tt>pb_ds</tt>'s default range-hashing - function is mask-based.</p> -<p><a href="assoc_performance_tests.html#hash_based_types">Observations::Hash-Based - Container Types</a> summarizes some observations on hash-based - containers; <a href="assoc_performance_tests.html#hash_based_policies">Observations::Hash-Based - Containers' Policies</a> summarizes some observations on - hash-based containers' policies.</p> -</div> -</body> -</html> |