CATCHING CONSPIRATORS

• Presented at TPM, Sept 30, 2004

• Presenter: Glenn Simpson gsimpson@mountaincable.net

• Slides generated by: slideshow.pl

• For information about slideshow.pl, contact

  Indigostar.com

THE BACKGROUND

• In the Sept issue of Dr Dobbs Journal, there is a column featuring Dr Ecco.

• The column presents puzzles for the reader's to solve.

• I select some of those puzzles and play with identifying a solution.

• The column implies that readers set down with pencil and paper and work out a solution.

• As I am computer and Perl oriented, I use the computer and Perl to assist me.

• In this issue, an informant has indicated there are conspirators.

• In this instant, 3 conspirators are ring leaders.

• The remaining conspirators are making their decisions based on the action of the ring leaders.

THE TRADES

• In the following table, a '1' represents a buy, and a '0' represents a sell

• There are 6 conspirators who have participated in 12 events.

• Table of trades

    conspirator 1  1 1 0 1 0 0 0 1 0 1 1 1
    conspirator 2  0 1 0 1 1 1 1 0 0 1 1 1
    conspirator 3  1 1 0 1 0 0 0 1 0 1 1 1
    conspirator 4  1 1 0 0 1 1 1 0 1 0 0 0
    conspirator 5  0 0 0 0 1 1 1 1 1 0 0 0
    conspirator 6  0 1 0 0 0 0 0 1 1 0 0 0
  

THE TOOLS OF THE FOLLOWERS

• We are told that the follower conspirators have no communications with the ring leaders.

• Each follower has a simple pair of logic boxes that they configure and then make a trade based on the result of the logic combo.

• A logic box performs either an AND on the inputs, or an ODD on the inputs.

• Here is an example of a 3 input AND box and an example of a 3 input ODD box

  

• If the 3 inputs to the AND box are a 'buy' then the output is a 'buy', else it is a sell.

• If the 3 inputs to the ODD box have an odd number of 'buy' transactions, then the output is a 'buy', else it is a 'sell'.

LOGIC COMBOS

• In addition to the 3 input AND, and 3 input ODD shown above, the following

      combinations can be configured if we have 3 ring leaders.
  

  

PERL TO THE ASSIST

• The following loops over the candidates, and proposes 3 ring leaders, which are passed to the evaluation function.

  local @aoa = (
      ["C1", 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1],
      ["C2", 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1],
      ["C3", 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1],
      ["C4", 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0],
      ["C5", 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
      ["C6", 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0]);
  
  $candidates = @aoa;
  
      # propose ring leaders
  for $rldr1 (0 .. $candidates - 2) {
     for($rldr2 = $rldr1 + 1; $rldr2 < $candidates - 1; $rldr2++) {
         for($rldr3 = $rldr2 + 1; $rldr3 < $candidates; $rldr3++) {
             test_logic3($rldr1, $rldr2, $rldr3);
         }
     }
  }
  

• Sub test_logic3() is where all the work is done.

EVALUATING CANDIDATES

     # evaluate each candidate that is not a proposed ring leader
 for($c = 0; $c < $candidates; $c++) {
   next if($rldr1 == $c || $rldr2 == $c || $rldr3 == $c);
                                                                                
   for $n (0 .. $rules) {          # init count of rule hits
     $ruleCnt[$c][$n] = 0;
   }
        # apply the rules to each event for this candidate
   for $e (1 .. $events) {         # column zero is not an event
     $tmp = ($aoa[$rldr1][$e] & $aoa[$rldr2][$e]) ? 1 : 0;
     $res[0] = ($aoa[$rldr3][$e] != $tmp) ? 1 : 0;   # 2 inp AND with ODD

     $tmp = $aoa[$rldr1][$e] & $aoa[$rldr3][$e];
     $res[1] = ($aoa[$rldr2][$e] != $tmp) ? 1 : 0;

     $tmp = $aoa[$rldr2][$e] & $aoa[$rldr3][$e];
     $res[2] = ($aoa[$rldr1][$e] != $tmp) ? 1 : 0;

     $res[3] = ($aoa[$rldr1][$e] + $aoa[$rldr2][$e] +
                $aoa[$rldr3][$e]) & 1;          # 3 inp ODD

EVALUATION CONT'D

     $res[4] = $aoa[$rldr1][$e] & $aoa[$rldr2][$e] & $aoa[$rldr3][$e]; # 3 inp AND

     $tmp = ($aoa[$rldr1][$e] + $aoa[$rldr2][$e]) & 1;  # 2 inp ODD with AND
     $res[5] = $aoa[$rldr3][$e] & $tmp;

     $tmp = ($aoa[$rldr1][$e] + $aoa[$rldr3][$e]) & 1;
     $res[6] = ($aoa[$rldr2][$e] & $tmp);

     $tmp = ($aoa[$rldr2][$e] + $aoa[$rldr3][$e]) & 1;
     $res[7] = ($aoa[$rldr1][$e] & $tmp);

     print " !! Rule results !!\n" if($debug > 2 && $e < 2);
     for($r = 0; $r < $rules; $r++) {     # count the rule hits
       print "( $res[$r] vs $aoa[$c][$e])" if($debug > 2);
       if($res[$r] == $aoa[$c][$e]) {
          $ruleCnt[$c][$r]++;     # add to the 'hit' count
       }
     }
     print "\n" if($debug > 2);
   }

EVALUATION CONT'D

  my $rcnt = 0;
  @ary = ();
  for($r = 0; $r < $rules; $r++) {   # collect list of follower conspirators
    print " rule $r: good $ruleCnt[$c][$r] times\n" if($debug > 1);
    next if($ruleCnt[$c][$r] < $events);
    $ary[$rcnt++] = $r;              # save which rule qualified
  }
  push @resTable, [@ary];
  print "Rules that qualified: @ary\n" if($debug && $rcnt);
                                                                                
  if($rcnt) {
    if($debug > 1) {
      my $cn = $c + 1;
      print "Rule(s) @ary qualify candidate $cn\n";
    }
  } else {
    return;     # ignore this leader combo
  }
 }

EVALUATION CONT'D

• Time to report the results

      my $cnt = 0;
      for($i = 0; $i < $#[$resTable]; $i++) {
          $cnt++ if($#[$resTable[$i]]);
      }
                                                                                  
      print " !! Final result !!\n  Leader $ldr1, $ldr2 and $ldr3 are ";
      my $ans = ($cnt < 2) ? "probably the leaders" : "not the leaders";
      print "$ans\n";
  }
  

SUMMARY

• The flexibility in Perl for generating loops

      foreach $i (@list)
  

      for $n ($low .. $high)
  

      for($x = 0; $x < $y; $x++)
  

      etc.
  

• The ease of building list of lists (array of arrays) and hash of hashes.

      push @mainList, [@subList];
  

• Simplicity of building a list of data.

      $ary[$cnt++] = $value;  
  

• I hope you have found this presentation a fun item to think about and maybe

      it represents yet another way to enjoy practicing your Perl skills.