Changes between Version 5 and Version 6 of BossaExampleTwo


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Timestamp:
Jul 30, 2008, 11:24:14 AM (16 years ago)
Author:
davea
Comment:

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  • BossaExampleTwo

    v5 v6  
    44but does replication to increase the accuracy of results.
    55Every job is sent to at least two different volunteers.
     6
     7We'll use the following replication policy:
     8 * A job is considered finished if either
     9  * Two volunteers reported "no ellipse found";
     10  * Two volunteers found ellipses, and their centers are within 20 pixels;
     11 * If ten instances have been performed and neither condition holds, the job is marked as "inconclusive" and no further instances are issued.
    612
    713We'll use the following job distribution policy:
    … …  
    1117 * When an instance times out, or finished but without consensus, we set the priority to 2.
    1218
    13 We'll use the following replication policy:
    14  * A job is considered finished if either
    15   * Two volunteers reported "no ellipse found";
    16   * Two volunteers found ellipses, and their centers are within 20 pixels;
    17  * If ten instances have been performed and neither condition holds, the job is marked as "inconclusive" and no further instances are issued.
     19The callback functions follow:
     20{{{
     21    30  function job_issued($job, $inst, $user) {
     22    31      $insts = $job->get_instances();
     23    32      if (count($insts) == 1) {
     24    33          $job->set_priority(2);
     25    34      } else {
     26    35          $job->set_priority(0);
     27    36      }
     28    37  }
    1829
    19 When the first instance of a job is issued, its priority is left at 1;
    20 this allows another instance to be issued immediately.
    21 {{{
    22 function job_issued($job, $inst, $user) {
    23     $insts = $job->get_instances();
    24     if (count($insts) > 1) {
    25         $job->set_priority(0);
    26     }
    27 }
    2830}}}
    29 
    3031
    3132When an instance is finished,
    … …  
    3536Otherwise we set its priority to 2, so that we'll get another instance.
    3637{{{
    37 function job_finished($job, $inst) {
    38     $response = null;
    39     if (get_str('submit', true)) {
    40         $response->have_ellipse = 0;
    41     } else {
    42         $response->have_ellipse = 1;
    43         $response->cx = get_int('pic_x');
    44         $response->cy = get_int('pic_y');
    45     }
    46     $inst->update_info($response);
    47 
    48     // see if job is done
    49     //
    50     $insts = $job->get_finished_instances();
    51     $n = count($insts);
    52 
    53     $results = null;
    54     foreach ($insts as $inst) {
    55         $results[] = $inst->get_info();
    56     }
    57     for ($i=0; $i<$n-1; $i++) {
    58         $r1 = $results[$i];
    59         for ($j=$i+1; $j<$n; $j++) {
    60             $r2 = $results[$j];
    61             if (compatible($r1, $r2)) {
    62                 $job->update_state(BOSSA_JOB_DONE);
    63                 return;
    64             }
    65         }
    66     }
    67     if ($n >= 10) {
    68         $job->update_state(BOSSA_JOB_INCONCLUSIVE);
    69         return;
    70     }
    71 }
    72 
    73 // two results are compatible if neither found an ellipse,
    74 // or they both did and centers are within 20 pixels
    75 //
    76 function compatible($r1, $r2) {
    77     if ($r1->have_ellipse) {
    78         if ($r2->have_ellipse) {
    79             $dx = ($r1->cx - $r2->cx);
    80             $dy = ($r1->cy - $r2->cy);
    81             $dsq = $dx*$dx + $dy*$dy;
    82             return ($dsq < 400);
    83         } else return false;
    84     } else {
    85         return !$r2->have_ellipse;
    86     }
    87 }
     38    39  function job_finished($job, $inst) {
     39    40      // record the user's response
     40    41      //
     41    42      $response = null;
     42    43      if (get_str('submit', true)) {
     43    44          $response->have_ellipse = 0;
     44    45      } else {
     45    46          $response->have_ellipse = 1;
     46    47          $response->cx = get_int('pic_x');
     47    48          $response->cy = get_int('pic_y');
     48    49      }
     49    50      $inst->set_opaque_data($response);
     50    51
     51    52      // see whether we have a consensus
     52    53      //
     53    54      $insts = $job->get_finished_instances();
     54    55      $n = count($insts);
     55    56
     56    57      $results = null;
     57    58      foreach ($insts as $inst) {
     58    59          $results[] = $inst->get_opaque_data();
     59    60      }
     60    61      for ($i=0; $i<$n-1; $i++) {
     61    62          $r1 = $results[$i];
     62    63          for ($j=$i+1; $j<$n; $j++) {
     63    64              $r2 = $results[$j];
     64    65              if (compatible($r1, $r2)) {
     65    66                  $job->set_state(BOSSA_JOB_DONE);
     66    67                  return;
     67    68              }
     68    69          }
     69    70      }
     70    71
     71    72      // no consensus - see whether we've reached replication limit
     72    73      //
     73    74      if ($n >= 10) {
     74    75          $job->set_state(BOSSA_JOB_INCONCLUSIVE);
     75    76          return;
     76    77      }
     77    78
     78    79      // still looking for consensus - allow another instance to be issued
     79    80      //
     80    81      $job->set_priority(2);
     81    82  }
     82    83
     83    84  // two results are compatible if neither found an ellipse,
     84    85  // or they both did and centers are within 20 pixels
     85    86  //
     86    87  function compatible($r1, $r2) {
     87    88      if ($r1->have_ellipse) {
     88    89          if ($r2->have_ellipse) {
     89    90              $dx = ($r1->cx - $r2->cx);
     90    91              $dy = ($r1->cy - $r2->cy);
     91    92              $dsq = $dx*$dx + $dy*$dy;
     92    93              return ($dsq < 400);
     93    94          } else return false;
     94    95      } else {
     95    96          return !$r2->have_ellipse;
     96    97      }
     97    98  }
    8898}}}