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+<a name="package-Graph::CyclesDetection-"></a>   1 <span class="k">package </span><span class="i">Graph::CyclesDetection</span><span class="sc">;</span>
+   2 <span class="c">#</span>
+   3 <span class="c"># $RCSfile: CyclesDetection.pm,v $</span>
+   4 <span class="c"># $Date: 2015/02/28 20:49:06 $</span>
+   5 <span class="c"># $Revision: 1.27 $</span>
+   6 <span class="c">#</span>
+   7 <span class="c"># Author: Manish Sud &lt;msud@san.rr.com&gt;</span>
+   8 <span class="c">#</span>
+   9 <span class="c"># Copyright (C) 2015 Manish Sud. All rights reserved.</span>
+  10 <span class="c">#</span>
+  11 <span class="c"># This file is part of MayaChemTools.</span>
+  12 <span class="c">#</span>
+  13 <span class="c"># MayaChemTools is free software; you can redistribute it and/or modify it under</span>
+  14 <span class="c"># the terms of the GNU Lesser General Public License as published by the Free</span>
+  15 <span class="c"># Software Foundation; either version 3 of the License, or (at your option) any</span>
+  16 <span class="c"># later version.</span>
+  17 <span class="c">#</span>
+  18 <span class="c"># MayaChemTools is distributed in the hope that it will be useful, but without</span>
+  19 <span class="c"># any warranty; without even the implied warranty of merchantability of fitness</span>
+  20 <span class="c"># for a particular purpose.  See the GNU Lesser General Public License for more</span>
+  21 <span class="c"># details.</span>
+  22 <span class="c">#</span>
+  23 <span class="c"># You should have received a copy of the GNU Lesser General Public License</span>
+  24 <span class="c"># along with MayaChemTools; if not, see &lt;http://www.gnu.org/licenses/&gt; or</span>
+  25 <span class="c"># write to the Free Software Foundation Inc., 59 Temple Place, Suite 330,</span>
+  26 <span class="c"># Boston, MA, 02111-1307, USA.</span>
+  27 <span class="c">#</span>
+  28 
+  29 <span class="k">use</span> <span class="w">strict</span><span class="sc">;</span>
+  30 <span class="k">use</span> <span class="w">Carp</span><span class="sc">;</span>
+  31 <span class="k">use</span> <span class="w">Exporter</span><span class="sc">;</span>
+  32 <span class="k">use</span> <span class="w">Graph</span><span class="sc">;</span>
+  33 <span class="k">use</span> <span class="w">Graph::Path</span><span class="sc">;</span>
+  34 <span class="k">use</span> <span class="w">Graph::PathGraph</span><span class="sc">;</span>
+  35 <span class="k">use</span> <span class="w">BitVector</span><span class="sc">;</span>
+  36 
+  37 <span class="k">use</span> <span class="w">vars</span> <span class="q">qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS)</span><span class="sc">;</span>
+  38 
+  39 <span class="i">@ISA</span> = <span class="q">qw(Exporter)</span><span class="sc">;</span>
+  40 <span class="i">@EXPORT</span> = <span class="q">qw()</span><span class="sc">;</span>
+  41 <span class="i">@EXPORT_OK</span> = <span class="q">qw()</span><span class="sc">;</span>
+  42 
+  43 <span class="i">%EXPORT_TAGS</span> = <span class="s">(</span><span class="w">all</span>  <span class="cm">=&gt;</span> <span class="s">[</span><span class="i">@EXPORT</span><span class="cm">,</span> <span class="i">@EXPORT_OK</span><span class="s">]</span><span class="s">)</span><span class="sc">;</span>
+  44 
+  45 <span class="c"># Setup class variables...</span>
+  46 <span class="k">my</span><span class="s">(</span><span class="i">$ClassName</span><span class="s">)</span><span class="sc">;</span>
+  47 <span class="i">_InitializeClass</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+  48 
+  49 <span class="c"># Overload Perl functions...</span>
+  50 <span class="k">use</span> <span class="w">overload</span> <span class="q">&#39;&quot;&quot;&#39;</span> <span class="cm">=&gt;</span> <span class="q">&#39;StringifyCyclesDetection&#39;</span><span class="sc">;</span>
+  51 
+  52 <span class="c"># Class constructor...</span>
+<a name="new-"></a>  53 <span class="k">sub </span><span class="m">new</span> <span class="s">{</span>
+  54   <span class="k">my</span><span class="s">(</span><span class="i">$Class</span><span class="cm">,</span> <span class="i">$Graph</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+  55 
+  56   <span class="c"># Initialize object...</span>
+  57   <span class="k">my</span> <span class="i">$This</span> = <span class="s">{</span><span class="s">}</span><span class="sc">;</span>
+  58   <span class="k">bless</span> <span class="i">$This</span><span class="cm">,</span> <span class="k">ref</span><span class="s">(</span><span class="i">$Class</span><span class="s">)</span> || <span class="i">$Class</span><span class="sc">;</span>
+  59   <span class="i">$This</span><span class="i">-&gt;_InitializeCyclesDetection</span><span class="s">(</span><span class="i">$Graph</span><span class="s">)</span><span class="sc">;</span>
+  60 
+  61   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span>
+  62 <span class="s">}</span>
+  63 
+  64 <span class="c"># Initialize object data...</span>
+<a name="_InitializeCyclesDetection-"></a>  65 <span class="k">sub </span><span class="m">_InitializeCyclesDetection</span> <span class="s">{</span>
+  66   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Graph</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+  67 
+  68   <span class="i">$This</span>-&gt;{<span class="w">Graph</span>} = <span class="i">$Graph</span><span class="sc">;</span>
+  69 
+  70   <span class="c"># Cycles list...</span>
+  71   <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}} = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+  72 
+  73   <span class="c"># Cyclic paths which are not part of any other cycle...</span>
+  74   <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}} = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+  75 
+  76   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span>
+  77 <span class="s">}</span>
+  78 
+  79 <span class="c"># Initialize class ...</span>
+<a name="_InitializeClass-"></a>  80 <span class="k">sub </span><span class="m">_InitializeClass</span> <span class="s">{</span>
+  81   <span class="c">#Class name...</span>
+  82   <span class="i">$ClassName</span> = <span class="w">__PACKAGE__</span><span class="sc">;</span>
+  83 <span class="s">}</span>
+  84 
+  85 <span class="c"># Detect all cycles in graph...</span>
+  86 <span class="c">#</span>
+<a name="DetectCycles-"></a>  87 <span class="k">sub </span><span class="m">DetectCycles</span> <span class="s">{</span>
+  88   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+  89 
+  90   <span class="k">return</span> <span class="i">$This</span><span class="i">-&gt;DetectCyclesUsingCollapsingPathGraphMethodology</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+  91 <span class="s">}</span>
+  92 
+  93 <span class="c"># Detect all cycles in the graph using collapsing path graph [Ref 31] methodology...</span>
+  94 <span class="c">#</span>
+  95 <span class="c"># Note:</span>
+  96 <span class="c">#   . For topologically complex graphs containing large number of cycles,</span>
+  97 <span class="c">#     CollapseVertexAndCollectCyclicPathsDetectCycles method implemented in</span>
+  98 <span class="c">#     PathGraph can time out in which case no cycles are detected or</span>
+  99 <span class="c">#     assigned.</span>
+ 100 <span class="c">#</span>
+<a name="DetectCyclesUsingCollapsingPathGraphMethodology-"></a> 101 <span class="k">sub </span><span class="m">DetectCyclesUsingCollapsingPathGraphMethodology</span> <span class="s">{</span>
+ 102   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 103   <span class="k">my</span><span class="s">(</span><span class="i">$PathGraph</span><span class="s">)</span><span class="sc">;</span>
+ 104 
+ 105   <span class="c"># Create a path graph...</span>
+ 106   <span class="i">$PathGraph</span> = <span class="i">new</span> <span class="i">Graph::PathGraph</span><span class="s">(</span><span class="i">$This</span>-&gt;{<span class="w">Graph</span>}<span class="s">)</span><span class="sc">;</span>
+ 107 
+ 108   <span class="c"># For a vertex to be in a cycle, its degree must be &gt;=2. So delete vertices recursively</span>
+ 109   <span class="c"># till all vertices with degree less than 2 have been deleted...</span>
+ 110   <span class="i">$PathGraph</span><span class="i">-&gt;DeleteVerticesWithDegreeLessThan</span><span class="s">(</span><span class="n">2</span><span class="s">)</span><span class="sc">;</span>
+ 111 
+ 112   <span class="c"># Setup a VertexID and EdgeID to index map usage during retrieval of independent cycles to</span>
+ 113   <span class="c"># avoid going over all vertices in all cylic paths later...</span>
+ 114   <span class="c">#</span>
+ 115   <span class="k">my</span><span class="s">(</span><span class="i">$VertexIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="cm">,</span> <span class="i">$EdgeIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestEdgeIDIndex</span><span class="s">)</span><span class="sc">;</span>
+ 116   <span class="s">(</span><span class="i">$VertexIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="s">)</span> = <span class="i">$This</span><span class="i">-&gt;_SetupVertexIDsToIndicesMap</span><span class="s">(</span><span class="i">$PathGraph</span><span class="s">)</span><span class="sc">;</span>
+ 117   <span class="s">(</span><span class="i">$EdgeIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestEdgeIDIndex</span><span class="s">)</span> = <span class="i">$This</span><span class="i">-&gt;_SetupEdgeIDsToIndicesMap</span><span class="s">(</span><span class="i">$PathGraph</span><span class="s">)</span><span class="sc">;</span>
+ 118 
+ 119   <span class="c"># Recursively collapse vertices with lowest degree...</span>
+ 120   <span class="k">my</span><span class="s">(</span><span class="i">$VertexID</span><span class="cm">,</span> <span class="i">$CycleVertexID</span><span class="s">)</span><span class="sc">;</span>
+ 121   <span class="k">while</span> <span class="s">(</span><span class="i">$VertexID</span> = <span class="i">$PathGraph</span><span class="i">-&gt;GetVertexWithSmallestDegree</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 122       <span class="k">if</span> <span class="s">(</span>!<span class="i">$PathGraph</span><span class="i">-&gt;CollapseVertexAndCollectCyclicPaths</span><span class="s">(</span><span class="i">$VertexID</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 123         <span class="c"># Cycles detection didn&#39;t finish...</span>
+ 124         <span class="k">return</span> <span class="k">undef</span><span class="sc">;</span>
+ 125       <span class="s">}</span>
+ 126   <span class="s">}</span>
+ 127 
+ 128   <span class="c"># Get detected cycles and save &#39;em sorted by size...</span>
+ 129   <span class="k">push</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="cm">,</span> <span class="k">sort</span> <span class="s">{</span> <span class="i">$a</span><span class="i">-&gt;GetLength</span><span class="s">(</span><span class="s">)</span> &lt;=&gt; <span class="i">$b</span><span class="i">-&gt;GetLength</span><span class="s">(</span><span class="s">)</span> <span class="s">}</span> <span class="i">$PathGraph</span><span class="i">-&gt;GetCyclicPaths</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 130 
+ 131   <span class="c"># Retrieve independent cyclic paths...</span>
+ 132   <span class="k">return</span> <span class="i">$This</span><span class="i">-&gt;_RetrieveIndependentCycles</span><span class="s">(</span><span class="i">$VertexIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="cm">,</span> <span class="i">$EdgeIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestEdgeIDIndex</span><span class="s">)</span><span class="sc">;</span>
+ 133 <span class="s">}</span>
+ 134 
+ 135 <span class="c"># Retrieve and save independent cyclic paths...</span>
+ 136 <span class="c">#</span>
+ 137 <span class="c"># Set of independent cycles identified using this method doesn&#39;t correspond to basis set of</span>
+ 138 <span class="c"># rings or smallest set of smallest rings (SSSR) [ Refs 29-30 ]; instead, set of cycles identified</span>
+ 139 <span class="c"># as independent cycles simply correspond to cycles which contain no other cycle as their</span>
+ 140 <span class="c"># subcycles and can&#39;t be described as linear combination of smaller cycles. And it also happen</span>
+ 141 <span class="c"># to contain all the rings in basis set of rings and SSSR. In other words, it&#39;s a superset of basis set</span>
+ 142 <span class="c"># of cycles and SSSR. For example, six four membered cycles are identified for cubane which is one</span>
+ 143 <span class="c"># more than the basis set of cycles.</span>
+ 144 <span class="c">#</span>
+<a name="_RetrieveIndependentCycles-"></a> 145 <span class="k">sub </span><span class="m">_RetrieveIndependentCycles</span> <span class="s">{</span>
+ 146   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$VertexIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="cm">,</span> <span class="i">$EdgeIDsToIndicesRef</span><span class="cm">,</span> <span class="i">$LargestEdgeIDIndex</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 147 
+ 148   <span class="c"># Only 1 or 0 cyclic paths...</span>
+ 149   <span class="k">if</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}} &lt;= <span class="n">1</span><span class="s">)</span> <span class="s">{</span>
+ 150     <span class="k">push</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="cm">,</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="sc">;</span>
+ 151     <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span>
+ 152   <span class="s">}</span>
+ 153 
+ 154   <span class="c"># Setup bit vectors for each cyclic path with size of each bit vector corresponding to</span>
+ 155   <span class="c"># maximum vertex index plus one...</span>
+ 156   <span class="k">my</span><span class="s">(</span><span class="i">$CyclicPath</span><span class="cm">,</span> <span class="i">$BitVector</span><span class="cm">,</span> <span class="i">@BitNums</span><span class="cm">,</span> <span class="i">@CyclicPathBitVectors</span><span class="cm">,</span> <span class="i">@CyclicPathEdgeIDsBitVectors</span><span class="s">)</span><span class="sc">;</span>
+ 157 
+ 158   <span class="i">@CyclicPathBitVectors</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">@CyclicPathEdgeIDsBitVectors</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 159 
+ 160   <span class="c"># Set bits corresponding to VertexIDs EdgeIDs using their indices...</span>
+ 161   <span class="k">for</span> <span class="i">$CyclicPath</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="s">)</span> <span class="s">{</span>
+ 162     <span class="i">$BitVector</span> = <span class="i">new</span> <span class="i">BitVector</span><span class="s">(</span><span class="i">$LargestVertexIndex</span><span class="s">)</span><span class="sc">;</span>
+ 163     <span class="i">@BitNums</span> = <span class="k">map</span> <span class="s">{</span> <span class="i">$VertexIDsToIndicesRef</span>-&gt;{<span class="i">$_</span>} <span class="s">}</span> <span class="i">$CyclicPath</span><span class="i">-&gt;GetVertices</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 164     <span class="i">$BitVector</span><span class="i">-&gt;SetBits</span><span class="s">(</span><span class="i">@BitNums</span><span class="s">)</span><span class="sc">;</span>
+ 165     <span class="k">push</span> <span class="i">@CyclicPathBitVectors</span><span class="cm">,</span> <span class="i">$BitVector</span><span class="sc">;</span>
+ 166 
+ 167     <span class="i">$BitVector</span> = <span class="i">new</span> <span class="i">BitVector</span><span class="s">(</span><span class="i">$LargestEdgeIDIndex</span><span class="s">)</span><span class="sc">;</span>
+ 168     <span class="i">@BitNums</span> = <span class="k">map</span> <span class="s">{</span> <span class="i">$EdgeIDsToIndicesRef</span>-&gt;{<span class="i">$_</span>} <span class="s">}</span> <span class="i">$This</span><span class="i">-&gt;_GetPathEdgeIDs</span><span class="s">(</span><span class="i">$CyclicPath</span><span class="s">)</span><span class="sc">;</span>
+ 169     <span class="i">$BitVector</span><span class="i">-&gt;SetBits</span><span class="s">(</span><span class="i">@BitNums</span><span class="s">)</span><span class="sc">;</span>
+ 170     <span class="k">push</span> <span class="i">@CyclicPathEdgeIDsBitVectors</span><span class="cm">,</span> <span class="i">$BitVector</span><span class="sc">;</span>
+ 171   <span class="s">}</span>
+ 172 
+ 173   <span class="c"># First smallest cyclic path always ends up as an independent cyclic path...</span>
+ 174   <span class="k">push</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="cm">,</span> <span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}[<span class="n">0</span>]<span class="sc">;</span>
+ 175 
+ 176   <span class="c"># Retrieve other independent cyclic paths...</span>
+ 177   <span class="k">my</span><span class="s">(</span><span class="i">$CurrentIndex</span><span class="cm">,</span> <span class="i">$PreviousIndex</span><span class="cm">,</span> <span class="i">$CurrentCyclicPath</span><span class="cm">,</span> <span class="i">$PreviousCyclicPath</span><span class="cm">,</span> <span class="i">$CurrentPathLength</span><span class="cm">,</span> <span class="i">$PreviousPathLength</span><span class="cm">,</span> <span class="i">$CurrentBitVector</span><span class="cm">,</span> <span class="i">$PreviousBitVector</span><span class="cm">,</span> <span class="i">$CurrentAndPreviousBitVectpor</span><span class="cm">,</span> <span class="i">$AllPreviousSmallerPathsBitVector</span><span class="cm">,</span> <span class="i">$AllPreviousSmallerPathsEdgeIDsBitVector</span><span class="cm">,</span> <span class="i">$CurrentEdgeIDsBitVector</span><span class="cm">,</span> <span class="i">$AndBitVector</span><span class="cm">,</span> <span class="i">%SmallerPathAlreadyAdded</span><span class="cm">,</span> <span class="i">%SkipPath</span><span class="s">)</span><span class="sc">;</span>
+ 178 
+ 179   <span class="i">%SkipPath</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 180   <span class="i">%SmallerPathAlreadyAdded</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 181   <span class="i">$AllPreviousSmallerPathsBitVector</span> = <span class="i">new</span> <span class="i">BitVector</span><span class="s">(</span><span class="i">$LargestVertexIndex</span><span class="s">)</span><span class="sc">;</span>
+ 182   <span class="i">$AllPreviousSmallerPathsEdgeIDsBitVector</span> = <span class="i">new</span> <span class="i">BitVector</span><span class="s">(</span><span class="i">$LargestEdgeIDIndex</span><span class="s">)</span><span class="sc">;</span>
+ 183 
+ 184   <span class="j">CURRENT:</span> <span class="k">for</span> <span class="i">$CurrentIndex</span> <span class="s">(</span><span class="n">1</span> .. <span class="i">$#</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="s">)</span> <span class="s">{</span>
+ 185     <span class="k">if</span> <span class="s">(</span><span class="k">exists</span> <span class="i">$SkipPath</span>{<span class="i">$CurrentIndex</span>}<span class="s">)</span> <span class="s">{</span>
+ 186       <span class="k">next</span> <span class="j">CURRENT</span><span class="sc">;</span>
+ 187     <span class="s">}</span>
+ 188     <span class="i">$CurrentCyclicPath</span> = <span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}[<span class="i">$CurrentIndex</span>]<span class="sc">;</span>
+ 189     <span class="i">$CurrentBitVector</span> = <span class="i">$CyclicPathBitVectors</span>[<span class="i">$CurrentIndex</span>]<span class="sc">;</span>
+ 190     <span class="i">$CurrentPathLength</span> = <span class="i">$CurrentCyclicPath</span><span class="i">-&gt;GetLength</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 191 
+ 192     <span class="j">PREVIOUS:</span> <span class="k">for</span> <span class="i">$PreviousIndex</span> <span class="s">(</span><span class="n">0</span> .. <span class="s">(</span><span class="i">$CurrentIndex</span> - <span class="n">1</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 193       <span class="k">if</span> <span class="s">(</span><span class="k">exists</span> <span class="i">$SkipPath</span>{<span class="i">$PreviousIndex</span>}<span class="s">)</span> <span class="s">{</span>
+ 194         <span class="k">next</span> <span class="j">PREVIOUS</span><span class="sc">;</span>
+ 195       <span class="s">}</span>
+ 196       <span class="i">$PreviousCyclicPath</span> = <span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}[<span class="i">$PreviousIndex</span>]<span class="sc">;</span>
+ 197       <span class="i">$PreviousBitVector</span> = <span class="i">$CyclicPathBitVectors</span>[<span class="i">$PreviousIndex</span>]<span class="sc">;</span>
+ 198 
+ 199       <span class="c"># Is previous path a subset of current path?</span>
+ 200       <span class="i">$CurrentAndPreviousBitVectpor</span> = <span class="i">$PreviousBitVector</span> &amp;  <span class="i">$CurrentBitVector</span><span class="sc">;</span>
+ 201       <span class="k">if</span> <span class="s">(</span><span class="i">$PreviousBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span> == <span class="i">$CurrentAndPreviousBitVectpor</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 202         <span class="c"># Current path doesn&#39;t qualify an independent path...</span>
+ 203         <span class="i">$SkipPath</span>{<span class="i">$CurrentIndex</span>} = <span class="n">1</span><span class="sc">;</span>
+ 204         <span class="k">next</span> <span class="j">CURRENT</span><span class="sc">;</span>
+ 205       <span class="s">}</span>
+ 206 
+ 207       <span class="i">$PreviousPathLength</span> = <span class="i">$PreviousCyclicPath</span><span class="i">-&gt;GetLength</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 208       <span class="k">if</span> <span class="s">(</span><span class="i">$PreviousPathLength</span> &lt; <span class="i">$CurrentPathLength</span><span class="s">)</span> <span class="s">{</span>
+ 209         <span class="c"># Mark cycle vertices seen in cyclic paths with length smaller than current path...</span>
+ 210         <span class="k">if</span> <span class="s">(</span>! <span class="k">exists</span> <span class="i">$SmallerPathAlreadyAdded</span>{<span class="i">$PreviousIndex</span>}<span class="s">)</span> <span class="s">{</span>
+ 211           <span class="i">$SmallerPathAlreadyAdded</span>{<span class="i">$PreviousIndex</span>} = <span class="n">1</span><span class="sc">;</span>
+ 212           <span class="i">$AllPreviousSmallerPathsBitVector</span> = <span class="i">$AllPreviousSmallerPathsBitVector</span> | <span class="i">$PreviousBitVector</span><span class="sc">;</span>
+ 213           <span class="i">$AllPreviousSmallerPathsEdgeIDsBitVector</span> = <span class="i">$AllPreviousSmallerPathsEdgeIDsBitVector</span> | <span class="i">$CyclicPathEdgeIDsBitVectors</span>[<span class="i">$PreviousIndex</span>]<span class="sc">;</span>
+ 214         <span class="s">}</span>
+ 215       <span class="s">}</span>
+ 216     <span class="s">}</span>
+ 217     <span class="k">if</span> <span class="s">(</span><span class="i">$AllPreviousSmallerPathsBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 218       <span class="c"># Is current path a linear combination of smaller paths?</span>
+ 219       <span class="i">$AndBitVector</span> = <span class="i">$AllPreviousSmallerPathsBitVector</span> &amp;  <span class="i">$CurrentBitVector</span><span class="sc">;</span>
+ 220       <span class="k">if</span> <span class="s">(</span><span class="i">$CurrentBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span> == <span class="i">$AndBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 221         <span class="c"># Are all edges in the current path already present in smaller paths?</span>
+ 222         <span class="i">$CurrentEdgeIDsBitVector</span> = <span class="i">$CyclicPathEdgeIDsBitVectors</span>[<span class="i">$CurrentIndex</span>]<span class="sc">;</span>
+ 223         <span class="i">$AndBitVector</span> = <span class="i">$AllPreviousSmallerPathsEdgeIDsBitVector</span> &amp;  <span class="i">$CurrentEdgeIDsBitVector</span><span class="sc">;</span>
+ 224 
+ 225         <span class="k">if</span> <span class="s">(</span><span class="i">$CurrentEdgeIDsBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span> == <span class="i">$AndBitVector</span><span class="i">-&gt;GetNumOfSetBits</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 226           <span class="c"># Current path doesn&#39;t qualify an independent path...</span>
+ 227           <span class="i">$SkipPath</span>{<span class="i">$CurrentIndex</span>} = <span class="n">1</span><span class="sc">;</span>
+ 228           <span class="k">next</span> <span class="j">CURRENT</span><span class="sc">;</span>
+ 229         <span class="s">}</span>
+ 230       <span class="s">}</span>
+ 231     <span class="s">}</span>
+ 232     <span class="c"># It&#39;s an independent cyclic path...</span>
+ 233     <span class="k">push</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="cm">,</span> <span class="i">$CurrentCyclicPath</span><span class="sc">;</span>
+ 234   <span class="s">}</span>
+ 235   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span>
+ 236 <span class="s">}</span>
+ 237 
+ 238 <span class="c"># Setup a VertexID to index map...</span>
+ 239 <span class="c">#</span>
+<a name="_SetupVertexIDsToIndicesMap-"></a> 240 <span class="k">sub </span><span class="m">_SetupVertexIDsToIndicesMap</span> <span class="s">{</span>
+ 241   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$PathGraph</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 242   <span class="k">my</span><span class="s">(</span><span class="i">$LargestVertexIndex</span><span class="cm">,</span> <span class="i">@VertexIDs</span><span class="cm">,</span> <span class="i">%VertexIDsMap</span><span class="s">)</span><span class="sc">;</span>
+ 243 
+ 244   <span class="i">%VertexIDsMap</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">@VertexIDs</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">$LargestVertexIndex</span> = <span class="n">0</span><span class="sc">;</span>
+ 245 
+ 246   <span class="i">@VertexIDs</span> = <span class="i">$PathGraph</span><span class="i">-&gt;GetVertices</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 247   <span class="k">if</span> <span class="s">(</span>! <span class="i">@VertexIDs</span><span class="s">)</span> <span class="s">{</span>
+ 248     <span class="k">return</span> <span class="s">(</span>\<span class="i">%VertexIDsMap</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="s">)</span><span class="sc">;</span>
+ 249   <span class="s">}</span>
+ 250   <span class="i">@VertexIDsMap</span>{ <span class="i">@VertexIDs</span> } = <span class="s">(</span><span class="n">0</span> .. <span class="i">$#VertexIDs</span><span class="s">)</span><span class="sc">;</span>
+ 251   <span class="i">$LargestVertexIndex</span> = <span class="k">scalar</span> <span class="i">@VertexIDs</span><span class="sc">;</span>
+ 252 
+ 253   <span class="k">return</span> <span class="s">(</span>\<span class="i">%VertexIDsMap</span><span class="cm">,</span> <span class="i">$LargestVertexIndex</span><span class="s">)</span><span class="sc">;</span>
+ 254 <span class="s">}</span>
+ 255 
+ 256 <span class="c"># Setup a Edge to index map using paths associated to egdes in an intial</span>
+ 257 <span class="c"># path graph...</span>
+ 258 <span class="c">#</span>
+<a name="_SetupEdgeIDsToIndicesMap-"></a> 259 <span class="k">sub </span><span class="m">_SetupEdgeIDsToIndicesMap</span> <span class="s">{</span>
+ 260   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$PathGraph</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 261   <span class="k">my</span><span class="s">(</span><span class="i">$Path</span><span class="cm">,</span> <span class="i">$LargestEdgeIndex</span><span class="cm">,</span> <span class="i">@EdgeIDs</span><span class="cm">,</span> <span class="i">%EdgeIDsMap</span><span class="s">)</span><span class="sc">;</span>
+ 262 
+ 263   <span class="i">%EdgeIDsMap</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">@EdgeIDs</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">$LargestEdgeIndex</span> = <span class="n">0</span><span class="sc">;</span>
+ 264 
+ 265   <span class="i">@EdgeIDs</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 266   <span class="k">for</span> <span class="i">$Path</span> <span class="s">(</span><span class="i">$PathGraph</span><span class="i">-&gt;GetPaths</span><span class="s">(</span><span class="s">)</span><span class="s">)</span> <span class="s">{</span>
+ 267     <span class="k">push</span> <span class="i">@EdgeIDs</span><span class="cm">,</span> <span class="i">$This</span><span class="i">-&gt;_GetPathEdgeIDs</span><span class="s">(</span><span class="i">$Path</span><span class="s">)</span><span class="sc">;</span>
+ 268   <span class="s">}</span>
+ 269 
+ 270   <span class="k">if</span> <span class="s">(</span>! <span class="i">@EdgeIDs</span><span class="s">)</span> <span class="s">{</span>
+ 271     <span class="k">return</span> <span class="s">(</span>\<span class="i">%EdgeIDsMap</span><span class="cm">,</span> <span class="i">$LargestEdgeIndex</span><span class="s">)</span><span class="sc">;</span>
+ 272   <span class="s">}</span>
+ 273 
+ 274   <span class="i">@EdgeIDsMap</span>{ <span class="i">@EdgeIDs</span> } = <span class="s">(</span><span class="n">0</span> .. <span class="i">$#EdgeIDs</span><span class="s">)</span><span class="sc">;</span>
+ 275   <span class="i">$LargestEdgeIndex</span> = <span class="k">scalar</span> <span class="i">@EdgeIDs</span><span class="sc">;</span>
+ 276 
+ 277   <span class="k">return</span> <span class="s">(</span>\<span class="i">%EdgeIDsMap</span><span class="cm">,</span> <span class="i">$LargestEdgeIndex</span><span class="s">)</span><span class="sc">;</span>
+ 278 <span class="s">}</span>
+ 279 
+ 280 <span class="c"># Get path edge IDs or number of edges. The edge IDs are generated from</span>
+ 281 <span class="c"># edge vertices and correpond to VertexID1-VertexID2 where VertexID1 &lt;=</span>
+ 282 <span class="c"># VertexID2.</span>
+ 283 <span class="c">#</span>
+<a name="_GetPathEdgeIDs-"></a> 284 <span class="k">sub </span><span class="m">_GetPathEdgeIDs</span> <span class="s">{</span>
+ 285   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Path</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 286   <span class="k">my</span><span class="s">(</span><span class="i">@EdgesVertexIDs</span><span class="cm">,</span> <span class="i">@EdgeIDs</span><span class="s">)</span><span class="sc">;</span>
+ 287 
+ 288   <span class="i">@EdgesVertexIDs</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="i">@EdgeIDs</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 289   <span class="i">@EdgesVertexIDs</span> = <span class="i">$Path</span><span class="i">-&gt;GetEdges</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span>
+ 290   <span class="k">if</span> <span class="s">(</span>!<span class="i">@EdgesVertexIDs</span><span class="s">)</span> <span class="s">{</span>
+ 291     <span class="k">return</span> <span class="k">wantarray</span> ? <span class="i">@EdgeIDs</span> <span class="co">:</span> <span class="s">(</span><span class="k">scalar</span> <span class="i">@EdgeIDs</span><span class="s">)</span><span class="sc">;</span>
+ 292   <span class="s">}</span>
+ 293 
+ 294   <span class="c"># Set up edge IDs...</span>
+ 295   <span class="k">my</span><span class="s">(</span><span class="i">$Index</span><span class="cm">,</span> <span class="i">$VertexID1</span><span class="cm">,</span> <span class="i">$VertexID2</span><span class="cm">,</span> <span class="i">$EdgeID</span><span class="s">)</span><span class="sc">;</span>
+ 296 
+ 297   <span class="k">for</span> <span class="s">(</span><span class="i">$Index</span> = <span class="n">0</span><span class="sc">;</span> <span class="i">$Index</span> &lt; <span class="i">$#EdgesVertexIDs</span><span class="sc">;</span> <span class="i">$Index</span> += <span class="n">2</span><span class="s">)</span> <span class="s">{</span>
+ 298     <span class="i">$VertexID1</span> = <span class="i">$EdgesVertexIDs</span>[<span class="i">$Index</span>]<span class="sc">;</span> <span class="i">$VertexID2</span> = <span class="i">$EdgesVertexIDs</span>[<span class="i">$Index</span> + <span class="n">1</span>]<span class="sc">;</span>
+ 299     <span class="i">$EdgeID</span> = <span class="s">(</span><span class="i">$VertexID1</span> &lt;= <span class="i">$VertexID2</span><span class="s">)</span> ? <span class="q">&quot;$VertexID1-$VertexID2&quot;</span> <span class="co">:</span> <span class="q">&quot;$VertexID2-$VertexID1&quot;</span><span class="sc">;</span>
+ 300     <span class="k">push</span> <span class="i">@EdgeIDs</span><span class="cm">,</span> <span class="i">$EdgeID</span><span class="sc">;</span>
+ 301   <span class="s">}</span>
+ 302 
+ 303   <span class="k">return</span> <span class="k">wantarray</span> ? <span class="i">@EdgeIDs</span> <span class="co">:</span> <span class="s">(</span><span class="k">scalar</span> <span class="i">@EdgeIDs</span><span class="s">)</span><span class="sc">;</span>
+ 304 <span class="s">}</span>
+ 305 
+ 306 <span class="c"># Return an array containing references to cyclic paths or number of cylic paths...</span>
+ 307 <span class="c">#</span>
+<a name="GetAllCyclicPaths-"></a> 308 <span class="k">sub </span><span class="m">GetAllCyclicPaths</span> <span class="s">{</span>
+ 309   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 310 
+ 311   <span class="k">return</span> <span class="k">wantarray</span> ? <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}} <span class="co">:</span> <span class="k">scalar</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="sc">;</span>
+ 312 <span class="s">}</span>
+ 313 
+ 314 <span class="c"># Get cyclic paths which are independent. In otherwords, cycles which don&#39;t contain any other</span>
+ 315 <span class="c"># cycle as their subset...</span>
+ 316 <span class="c">#</span>
+<a name="GetIndependentCyclicPaths-"></a> 317 <span class="k">sub </span><span class="m">GetIndependentCyclicPaths</span> <span class="s">{</span>
+ 318   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 319 
+ 320   <span class="k">return</span> <span class="k">wantarray</span> ? <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}} <span class="co">:</span> <span class="k">scalar</span> <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="sc">;</span>
+ 321 <span class="s">}</span>
+ 322 
+ 323 <span class="c"># Return a string containg data for CyclesDetection object...</span>
+<a name="StringifyCyclesDetection-"></a> 324 <span class="k">sub </span><span class="m">StringifyCyclesDetection</span> <span class="s">{</span>
+ 325   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 326   <span class="k">my</span><span class="s">(</span><span class="i">$CyclesDetectionString</span><span class="cm">,</span> <span class="i">$CyclesCount</span><span class="cm">,</span> <span class="i">$CyclicPath</span><span class="s">)</span><span class="sc">;</span>
+ 327 
+ 328   <span class="i">$CyclesCount</span> = <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="sc">;</span>
+ 329   <span class="i">$CyclesDetectionString</span> = <span class="q">&quot;AllCycles: Count - $CyclesCount&quot;</span><span class="sc">;</span>
+ 330   <span class="k">for</span> <span class="i">$CyclicPath</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">AllCyclicPaths</span>}}<span class="s">)</span> <span class="s">{</span>
+ 331     <span class="i">$CyclesDetectionString</span> .= <span class="q">&quot;; Cycle: &quot;</span> . <span class="k">join</span><span class="s">(</span><span class="q">&#39;-&#39;</span><span class="cm">,</span> <span class="i">$CyclicPath</span><span class="i">-&gt;GetVertices</span><span class="s">(</span><span class="s">)</span><span class="s">)</span><span class="sc">;</span>
+ 332   <span class="s">}</span>
+ 333 
+ 334   <span class="i">$CyclesCount</span> = <span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="sc">;</span>
+ 335   <span class="i">$CyclesDetectionString</span> .= <span class="q">&quot;\nIndependentCycles: Count - $CyclesCount&quot;</span><span class="sc">;</span>
+ 336   <span class="k">for</span> <span class="i">$CyclicPath</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>-&gt;{<span class="w">IndependentCyclicPaths</span>}}<span class="s">)</span> <span class="s">{</span>
+ 337     <span class="i">$CyclesDetectionString</span> .= <span class="q">&quot;; Cycle: &quot;</span> . <span class="k">join</span><span class="s">(</span><span class="q">&#39;-&#39;</span><span class="cm">,</span> <span class="i">$CyclicPath</span><span class="i">-&gt;GetVertices</span><span class="s">(</span><span class="s">)</span><span class="s">)</span><span class="sc">;</span>
+ 338   <span class="s">}</span>
+ 339 
+ 340   <span class="k">return</span> <span class="i">$CyclesDetectionString</span><span class="sc">;</span>
+ 341 <span class="s">}</span>
+ 342 
+ 343 <span class="c"># Return a reference to new cycle detection object...</span>
+<a name="Copy-"></a> 344 <span class="k">sub </span><span class="m">Copy</span> <span class="s">{</span>
+ 345   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span>
+ 346   <span class="k">my</span><span class="s">(</span><span class="i">$NewCyclesDetection</span><span class="s">)</span><span class="sc">;</span>
+ 347 
+ 348   <span class="i">$NewCyclesDetection</span> = <span class="i">Storable::dclone</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span><span class="sc">;</span>
+ 349 
+ 350   <span class="k">return</span> <span class="i">$NewCyclesDetection</span><span class="sc">;</span>
+ 351 <span class="s">}</span>
+ 352 
+<a name="EOF-"></a></pre>
+<p>&nbsp;</p>
+<br />
+<center>
+<img src="../../../images/h2o2.png">
+</center>
+</body>
+</html>