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<a href="probing_8h.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2010-2018 Google LLC</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment">// Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment">// you may not use this file except in compliance with the License.</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment">// You may obtain a copy of the License at</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;<span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="comment">// distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;<span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="comment">// See the License for the specific language governing permissions and</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;<span class="comment">// limitations under the License.</span></div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160; </div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;<span class="preprocessor">#ifndef OR_TOOLS_SAT_PROBING_H_</span></div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="preprocessor">#define OR_TOOLS_SAT_PROBING_H_</span></div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160; </div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span>&#160;<span class="preprocessor">#include &quot;absl/types/span.h&quot;</span></div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span>&#160;<span class="preprocessor">#include &quot;<a class="code" href="sat_2model_8h.html">ortools/sat/model.h</a>&quot;</span></div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span>&#160;<span class="preprocessor">#include &quot;<a class="code" href="sat__base_8h.html">ortools/sat/sat_base.h</a>&quot;</span></div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span>&#160; </div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span>&#160;<span class="keyword">namespace </span><a class="code" href="namespaceoperations__research.html">operations_research</a> {</div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span>&#160;<span class="keyword">namespace </span>sat {</div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span>&#160; </div>
<div class="line"><a name="l00024"></a><span class="lineno"> 24</span>&#160;<span class="comment">// Fixes Booleans variables to true/false and see what is propagated. This can:</span></div>
<div class="line"><a name="l00025"></a><span class="lineno"> 25</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span>&#160;<span class="comment">// - Fix some Boolean variables (if we reach a conflict while probing).</span></div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span>&#160;<span class="comment">// - Infer new direct implications. We add them directly to the</span></div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160;<span class="comment">// BinaryImplicationGraph and they can later be used to detect equivalent</span></div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span>&#160;<span class="comment">// literals, expand at most ones clique, etc...</span></div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160;<span class="comment">// - Tighten the bounds of integer variables. If we probe the two possible</span></div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span>&#160;<span class="comment">// values of a Boolean (b=0 and b=1), we get for each integer variables two</span></div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160;<span class="comment">// propagated domain D_0 and D_1. The level zero domain can then be</span></div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160;<span class="comment">// intersected with D_0 U D_1. This can restrict the lower/upper bounds of a</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span>&#160;<span class="comment">// variable, but it can also create holes in the domain! This will detect</span></div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160;<span class="comment">// common cases like an integer variable in [0, 10] that actually only take</span></div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span>&#160;<span class="comment">// two values [0] or [10] depending on one Boolean.</span></div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160;<span class="comment">// Returns false if the problem was proved INFEASIBLE during probing.</span></div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160;<span class="comment">// TODO(user): For now we process the Boolean in their natural order, this is</span></div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160;<span class="comment">// not the most efficient.</span></div>
<div class="line"><a name="l00044"></a><span class="lineno"> 44</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160;<span class="comment">// TODO(user): This might generate a lot of new direct implications. We might</span></div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span>&#160;<span class="comment">// not want to add them directly to the BinaryImplicationGraph and could instead</span></div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160;<span class="comment">// use them directly to detect equivalent literal like in</span></div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160;<span class="comment">// ProbeAndFindEquivalentLiteral(). The situation is not clear.</span></div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span>&#160;<span class="comment">// TODO(user): More generally, we might want to register any literal =&gt; bound in</span></div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160;<span class="comment">// the IntegerEncoder. This would allow to remember them and use them in other</span></div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160;<span class="comment">// part of the solver (cuts, lifting, ...).</span></div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>&#160;<span class="comment">// TODO(user): Rename to include Integer in the name and distinguish better</span></div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160;<span class="comment">// from FailedLiteralProbing() below.</span></div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160;<span class="keywordtype">bool</span> <a class="code" href="namespaceoperations__research_1_1sat.html#a33bff3781b729e27219201cf5a05a140">ProbeBooleanVariables</a>(<span class="keywordtype">double</span> deterministic_time_limit, Model* <a class="code" href="gurobi__interface_8cc.html#a0728f23c9a47655d38e0bf1a2f200bcf">model</a>,</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160; <span class="keywordtype">bool</span> log_info = <span class="keyword">false</span>);</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>&#160; </div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span>&#160;<span class="comment">// Same as above method except it probes only on the variables given in</span></div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span>&#160;<span class="comment">// &#39;bool_vars&#39;.</span></div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span>&#160;<span class="keywordtype">bool</span> <a class="code" href="namespaceoperations__research_1_1sat.html#a33bff3781b729e27219201cf5a05a140">ProbeBooleanVariables</a>(<span class="keywordtype">double</span> deterministic_time_limit,</div>
<div class="line"><a name="l00062"></a><span class="lineno"> 62</span>&#160; absl::Span&lt;const BooleanVariable&gt; bool_vars,</div>
<div class="line"><a name="l00063"></a><span class="lineno"> 63</span>&#160; Model* <a class="code" href="gurobi__interface_8cc.html#a0728f23c9a47655d38e0bf1a2f200bcf">model</a>, <span class="keywordtype">bool</span> log_info = <span class="keyword">false</span>);</div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span>&#160; </div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span>&#160;<span class="comment">// Try to randomly tweak the search and stop at the first conflict each time.</span></div>
<div class="line"><a name="l00066"></a><span class="lineno"> 66</span>&#160;<span class="comment">// This can sometimes find feasible solution, but more importantly, it is a form</span></div>
<div class="line"><a name="l00067"></a><span class="lineno"> 67</span>&#160;<span class="comment">// of probing that can sometimes find small and interesting conflicts or fix</span></div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span>&#160;<span class="comment">// variables. This seems to work well on the SAT14/app/rook-* problems and</span></div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&#160;<span class="comment">// do fix more variables if run before probing.</span></div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>&#160;<span class="comment">// If a feasible SAT solution is found (i.e. all Boolean assigned), then this</span></div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>&#160;<span class="comment">// abort and leave the solver with the full solution assigned.</span></div>
<div class="line"><a name="l00073"></a><span class="lineno"> 73</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00074"></a><span class="lineno"> 74</span>&#160;<span class="comment">// Returns false iff the problem is UNSAT.</span></div>
<div class="line"><a name="l00075"></a><span class="lineno"> 75</span>&#160;<span class="keywordtype">bool</span> <a class="code" href="namespaceoperations__research_1_1sat.html#a20296d1a269e973b66b403c8b1cd5785">LookForTrivialSatSolution</a>(<span class="keywordtype">double</span> deterministic_time_limit, Model* <a class="code" href="gurobi__interface_8cc.html#a0728f23c9a47655d38e0bf1a2f200bcf">model</a>,</div>
<div class="line"><a name="l00076"></a><span class="lineno"> 76</span>&#160; <span class="keywordtype">bool</span> log_info = <span class="keyword">false</span>);</div>
<div class="line"><a name="l00077"></a><span class="lineno"> 77</span>&#160; </div>
<div class="line"><a name="l00078"></a><span class="lineno"> 78</span>&#160;<span class="comment">// Options for the FailedLiteralProbing() code below.</span></div>
<div class="line"><a name="l00079"></a><span class="lineno"> 79</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00080"></a><span class="lineno"> 80</span>&#160;<span class="comment">// A good reference for the algorithms involved here is the paper &quot;Revisiting</span></div>
<div class="line"><a name="l00081"></a><span class="lineno"> 81</span>&#160;<span class="comment">// Hyper Binary Resolution&quot; Marijn J. H. Heule, Matti Jarvisalo, Armin Biere,</span></div>
<div class="line"><a name="l00082"></a><span class="lineno"> 82</span>&#160;<span class="comment">// http://www.cs.utexas.edu/~marijn/cpaior2013.pdf</span></div>
<div class="line"><a name="l00083"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html"> 83</a></span>&#160;<span class="keyword">struct </span><a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html">ProbingOptions</a> {</div>
<div class="line"><a name="l00084"></a><span class="lineno"> 84</span>&#160; <span class="comment">// The probing will consume all this deterministic time or stop if nothing</span></div>
<div class="line"><a name="l00085"></a><span class="lineno"> 85</span>&#160; <span class="comment">// else can be deduced and everything has been probed until fix-point. The</span></div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span>&#160; <span class="comment">// fix point depend on the extract_binay_clauses option:</span></div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span>&#160; <span class="comment">// - If false, we will just stop when no more failed literal can be found.</span></div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span>&#160; <span class="comment">// - If true, we will do more work and stop when all failed literal have been</span></div>
<div class="line"><a name="l00089"></a><span class="lineno"> 89</span>&#160; <span class="comment">// found and all hyper binary resolution have been performed.</span></div>
<div class="line"><a name="l00090"></a><span class="lineno"> 90</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00091"></a><span class="lineno"> 91</span>&#160; <span class="comment">// TODO(user): We can also provide a middle ground and probe all failed</span></div>
<div class="line"><a name="l00092"></a><span class="lineno"> 92</span>&#160; <span class="comment">// literal but do not extract all binary clauses.</span></div>
<div class="line"><a name="l00093"></a><span class="lineno"> 93</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00094"></a><span class="lineno"> 94</span>&#160; <span class="comment">// Note that the fix-point is unique, modulo the equivalent literal detection</span></div>
<div class="line"><a name="l00095"></a><span class="lineno"> 95</span>&#160; <span class="comment">// we do. And if we add binary clauses, modulo the transitive reduction of the</span></div>
<div class="line"><a name="l00096"></a><span class="lineno"> 96</span>&#160; <span class="comment">// binary implication graph.</span></div>
<div class="line"><a name="l00097"></a><span class="lineno"> 97</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00098"></a><span class="lineno"> 98</span>&#160; <span class="comment">// To be fast, we only use the binary clauses in the binary implication graph</span></div>
<div class="line"><a name="l00099"></a><span class="lineno"> 99</span>&#160; <span class="comment">// for the equivalence detection. So the power of the equivalence detection</span></div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>&#160; <span class="comment">// changes if the extract_binay_clauses option is true or not.</span></div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00102"></a><span class="lineno"> 102</span>&#160; <span class="comment">// TODO(user): The fix point is not yet reached since we don&#39;t currently</span></div>
<div class="line"><a name="l00103"></a><span class="lineno"> 103</span>&#160; <span class="comment">// simplify non-binary clauses with these equivalence, but we will.</span></div>
<div class="line"><a name="l00104"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a4f572c68b7bf3aac70b3f5292398ff7b"> 104</a></span>&#160; <span class="keywordtype">double</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a4f572c68b7bf3aac70b3f5292398ff7b">deterministic_limit</a> = 1.0;</div>
<div class="line"><a name="l00105"></a><span class="lineno"> 105</span>&#160; </div>
<div class="line"><a name="l00106"></a><span class="lineno"> 106</span>&#160; <span class="comment">// This is also called hyper binary resolution. Basically, we make sure that</span></div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span>&#160; <span class="comment">// the binary implication graph is augmented with all the implication of the</span></div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>&#160; <span class="comment">// form a =&gt; b that can be derived by fixing &#39;a&#39; at level zero and doing a</span></div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>&#160; <span class="comment">// propagation using all constraints. Note that we only add clauses that</span></div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>&#160; <span class="comment">// cannot be derived by the current implication graph.</span></div>
<div class="line"><a name="l00111"></a><span class="lineno"> 111</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00112"></a><span class="lineno"> 112</span>&#160; <span class="comment">// With these extra clause the power of the equivalence literal detection</span></div>
<div class="line"><a name="l00113"></a><span class="lineno"> 113</span>&#160; <span class="comment">// using only the binary implication graph with increase. Note that it is</span></div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>&#160; <span class="comment">// possible to do exactly the same thing without adding these binary clause</span></div>
<div class="line"><a name="l00115"></a><span class="lineno"> 115</span>&#160; <span class="comment">// first. This is what is done by yet another probing algorithm (currently in</span></div>
<div class="line"><a name="l00116"></a><span class="lineno"> 116</span>&#160; <span class="comment">// simplification.cc).</span></div>
<div class="line"><a name="l00117"></a><span class="lineno"> 117</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00118"></a><span class="lineno"> 118</span>&#160; <span class="comment">// TODO(user): Note that adding binary clause before/during the SAT presolve</span></div>
<div class="line"><a name="l00119"></a><span class="lineno"> 119</span>&#160; <span class="comment">// is currently not always a good idea. This is because we don&#39;t simplify the</span></div>
<div class="line"><a name="l00120"></a><span class="lineno"> 120</span>&#160; <span class="comment">// other clause as much as we could. Also, there can be up to a quadratic</span></div>
<div class="line"><a name="l00121"></a><span class="lineno"> 121</span>&#160; <span class="comment">// number of clauses added this way, which might slow down things a lot. But</span></div>
<div class="line"><a name="l00122"></a><span class="lineno"> 122</span>&#160; <span class="comment">// then because of the deterministic limit, we usually cannot add too much</span></div>
<div class="line"><a name="l00123"></a><span class="lineno"> 123</span>&#160; <span class="comment">// clauses, even for huge problems, since we will reach the limit before that.</span></div>
<div class="line"><a name="l00124"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a9d4ed6726cbb0ec29c0d62faec4b6405"> 124</a></span>&#160; <span class="keywordtype">bool</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a9d4ed6726cbb0ec29c0d62faec4b6405">extract_binary_clauses</a> = <span class="keyword">false</span>;</div>
<div class="line"><a name="l00125"></a><span class="lineno"> 125</span>&#160; </div>
<div class="line"><a name="l00126"></a><span class="lineno"> 126</span>&#160; <span class="comment">// Use a version of the &quot;Tree look&quot; algorithm as explained in the paper above.</span></div>
<div class="line"><a name="l00127"></a><span class="lineno"> 127</span>&#160; <span class="comment">// This is usually faster and more efficient. Note that when extracting binary</span></div>
<div class="line"><a name="l00128"></a><span class="lineno"> 128</span>&#160; <span class="comment">// clauses it might currently produce more &quot;redundant&quot; one in the sense that a</span></div>
<div class="line"><a name="l00129"></a><span class="lineno"> 129</span>&#160; <span class="comment">// transitive reduction of the binary implication graph after all hyper binary</span></div>
<div class="line"><a name="l00130"></a><span class="lineno"> 130</span>&#160; <span class="comment">// resolution have been performed may need to do more work.</span></div>
<div class="line"><a name="l00131"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a935644a2da13a1ac84cb06649b840283"> 131</a></span>&#160; <span class="keywordtype">bool</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a935644a2da13a1ac84cb06649b840283">use_tree_look</a> = <span class="keyword">true</span>;</div>
<div class="line"><a name="l00132"></a><span class="lineno"> 132</span>&#160; </div>
<div class="line"><a name="l00133"></a><span class="lineno"> 133</span>&#160; <span class="comment">// There is two sligthly different implementation of the tree-look algo.</span></div>
<div class="line"><a name="l00134"></a><span class="lineno"> 134</span>&#160; <span class="comment">//</span></div>
<div class="line"><a name="l00135"></a><span class="lineno"> 135</span>&#160; <span class="comment">// TODO(user): Decide which one is better, currently the difference seems</span></div>
<div class="line"><a name="l00136"></a><span class="lineno"> 136</span>&#160; <span class="comment">// small but the queue seems slightly faster.</span></div>
<div class="line"><a name="l00137"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19601d926c1322ba3e11da2a386397dd"> 137</a></span>&#160; <span class="keywordtype">bool</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19601d926c1322ba3e11da2a386397dd">use_queue</a> = <span class="keyword">true</span>;</div>
<div class="line"><a name="l00138"></a><span class="lineno"> 138</span>&#160; </div>
<div class="line"><a name="l00139"></a><span class="lineno"> 139</span>&#160; <span class="comment">// If we detect as we probe that a new binary clause subsumes one of the</span></div>
<div class="line"><a name="l00140"></a><span class="lineno"> 140</span>&#160; <span class="comment">// non-binary clause, we will replace the long clause by the binary one. This</span></div>
<div class="line"><a name="l00141"></a><span class="lineno"> 141</span>&#160; <span class="comment">// is orthogonal to the extract_binary_clauses parameters which will add all</span></div>
<div class="line"><a name="l00142"></a><span class="lineno"> 142</span>&#160; <span class="comment">// binary clauses but not neceassirly check for subsumption.</span></div>
<div class="line"><a name="l00143"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a63d303690279f2933007e2dde7f28541"> 143</a></span>&#160; <span class="keywordtype">bool</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a63d303690279f2933007e2dde7f28541">subsume_with_binary_clause</a> = <span class="keyword">true</span>;</div>
<div class="line"><a name="l00144"></a><span class="lineno"> 144</span>&#160; </div>
<div class="line"><a name="l00145"></a><span class="lineno"> 145</span>&#160; <span class="comment">// We assume this is also true if --v 1 is activated.</span></div>
<div class="line"><a name="l00146"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a54320231778412ca00e50eb821c95aa6"> 146</a></span>&#160; <span class="keywordtype">bool</span> <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a54320231778412ca00e50eb821c95aa6">log_info</a> = <span class="keyword">false</span>;</div>
<div class="line"><a name="l00147"></a><span class="lineno"> 147</span>&#160; </div>
<div class="line"><a name="l00148"></a><span class="lineno"><a class="line" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19c380b03cea21d7ac7325136a131ff0"> 148</a></span>&#160; std::string <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19c380b03cea21d7ac7325136a131ff0">ToString</a>()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00149"></a><span class="lineno"> 149</span>&#160; <span class="keywordflow">return</span> absl::StrCat(<span class="stringliteral">&quot;deterministic_limit: &quot;</span>, <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a4f572c68b7bf3aac70b3f5292398ff7b">deterministic_limit</a>,</div>
<div class="line"><a name="l00150"></a><span class="lineno"> 150</span>&#160; <span class="stringliteral">&quot; extract_binary_clauses: &quot;</span>, <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a9d4ed6726cbb0ec29c0d62faec4b6405">extract_binary_clauses</a>,</div>
<div class="line"><a name="l00151"></a><span class="lineno"> 151</span>&#160; <span class="stringliteral">&quot; use_tree_look: &quot;</span>, <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a935644a2da13a1ac84cb06649b840283">use_tree_look</a>,</div>
<div class="line"><a name="l00152"></a><span class="lineno"> 152</span>&#160; <span class="stringliteral">&quot; use_queue: &quot;</span>, <a class="code" href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19601d926c1322ba3e11da2a386397dd">use_queue</a>);</div>
<div class="line"><a name="l00153"></a><span class="lineno"> 153</span>&#160; }</div>
<div class="line"><a name="l00154"></a><span class="lineno"> 154</span>&#160;};</div>
<div class="line"><a name="l00155"></a><span class="lineno"> 155</span>&#160; </div>
<div class="line"><a name="l00156"></a><span class="lineno"> 156</span>&#160;<span class="comment">// Similar to ProbeBooleanVariables() but different :-)</span></div>
<div class="line"><a name="l00157"></a><span class="lineno"> 157</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00158"></a><span class="lineno"> 158</span>&#160;<span class="comment">// First, this do not consider integer variable. It doesn&#39;t do any disjunctive</span></div>
<div class="line"><a name="l00159"></a><span class="lineno"> 159</span>&#160;<span class="comment">// reasoning (i.e. changing the domain of an integer variable by intersecting it</span></div>
<div class="line"><a name="l00160"></a><span class="lineno"> 160</span>&#160;<span class="comment">// with the union of what happen when x is fixed and not(x) is fixed).</span></div>
<div class="line"><a name="l00161"></a><span class="lineno"> 161</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00162"></a><span class="lineno"> 162</span>&#160;<span class="comment">// However this should be more efficient and just work better for pure Boolean</span></div>
<div class="line"><a name="l00163"></a><span class="lineno"> 163</span>&#160;<span class="comment">// problems. On integer problems, we might also want to run this one first, and</span></div>
<div class="line"><a name="l00164"></a><span class="lineno"> 164</span>&#160;<span class="comment">// then do just one quick pass of ProbeBooleanVariables().</span></div>
<div class="line"><a name="l00165"></a><span class="lineno"> 165</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00166"></a><span class="lineno"> 166</span>&#160;<span class="comment">// Note that this by itself just do one &quot;round&quot;, look at the code in the</span></div>
<div class="line"><a name="l00167"></a><span class="lineno"> 167</span>&#160;<span class="comment">// Inprocessing class that call this interleaved with other reductions until a</span></div>
<div class="line"><a name="l00168"></a><span class="lineno"> 168</span>&#160;<span class="comment">// fix point is reached.</span></div>
<div class="line"><a name="l00169"></a><span class="lineno"> 169</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00170"></a><span class="lineno"> 170</span>&#160;<span class="comment">// This can fix a lot of literals via failed literal detection, that is when we</span></div>
<div class="line"><a name="l00171"></a><span class="lineno"> 171</span>&#160;<span class="comment">// detect that x =&gt; not(x) via propagation after taking x as a decision. It also</span></div>
<div class="line"><a name="l00172"></a><span class="lineno"> 172</span>&#160;<span class="comment">// use the strongly connected component algorithm to detect equivalent literals.</span></div>
<div class="line"><a name="l00173"></a><span class="lineno"> 173</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00174"></a><span class="lineno"> 174</span>&#160;<span class="comment">// It will add any detected binary clause (via hyper binary resolution) to</span></div>
<div class="line"><a name="l00175"></a><span class="lineno"> 175</span>&#160;<span class="comment">// the implication graph. See the option comments for more details.</span></div>
<div class="line"><a name="l00176"></a><span class="lineno"> 176</span>&#160;<span class="keywordtype">bool</span> <a class="code" href="namespaceoperations__research_1_1sat.html#a865df3eeca0b96bf7fda22b016b80bc2">FailedLiteralProbingRound</a>(ProbingOptions options, Model* <a class="code" href="gurobi__interface_8cc.html#a0728f23c9a47655d38e0bf1a2f200bcf">model</a>);</div>
<div class="line"><a name="l00177"></a><span class="lineno"> 177</span>&#160; </div>
<div class="line"><a name="l00178"></a><span class="lineno"> 178</span>&#160;} <span class="comment">// namespace sat</span></div>
<div class="line"><a name="l00179"></a><span class="lineno"> 179</span>&#160;} <span class="comment">// namespace operations_research</span></div>
<div class="line"><a name="l00180"></a><span class="lineno"> 180</span>&#160; </div>
<div class="line"><a name="l00181"></a><span class="lineno"> 181</span>&#160;<span class="preprocessor">#endif // OR_TOOLS_SAT_PROBING_H_</span></div>
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<div class="ttc" id="anamespaceoperations__research_1_1sat_html_a865df3eeca0b96bf7fda22b016b80bc2"><div class="ttname"><a href="namespaceoperations__research_1_1sat.html#a865df3eeca0b96bf7fda22b016b80bc2">operations_research::sat::FailedLiteralProbingRound</a></div><div class="ttdeci">bool FailedLiteralProbingRound(ProbingOptions options, Model *model)</div><div class="ttdef"><b>Definition:</b> <a href="probing_8cc_source.html#l00338">probing.cc:338</a></div></div>
<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a19c380b03cea21d7ac7325136a131ff0"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19c380b03cea21d7ac7325136a131ff0">operations_research::sat::ProbingOptions::ToString</a></div><div class="ttdeci">std::string ToString() const</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00148">probing.h:148</a></div></div>
<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a4f572c68b7bf3aac70b3f5292398ff7b"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a4f572c68b7bf3aac70b3f5292398ff7b">operations_research::sat::ProbingOptions::deterministic_limit</a></div><div class="ttdeci">double deterministic_limit</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00104">probing.h:104</a></div></div>
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<div class="ttc" id="asat_2model_8h_html"><div class="ttname"><a href="sat_2model_8h.html">model.h</a></div></div>
<div class="ttc" id="anamespaceoperations__research_html"><div class="ttname"><a href="namespaceoperations__research.html">operations_research</a></div><div class="ttdoc">The vehicle routing library lets one model and solve generic vehicle routing problems ranging from th...</div><div class="ttdef"><b>Definition:</b> <a href="dense__doubly__linked__list_8h_source.html#l00021">dense_doubly_linked_list.h:21</a></div></div>
<div class="ttc" id="asat__base_8h_html"><div class="ttname"><a href="sat__base_8h.html">sat_base.h</a></div></div>
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<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a54320231778412ca00e50eb821c95aa6"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a54320231778412ca00e50eb821c95aa6">operations_research::sat::ProbingOptions::log_info</a></div><div class="ttdeci">bool log_info</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00146">probing.h:146</a></div></div>
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<div class="ttc" id="agurobi__interface_8cc_html_a0728f23c9a47655d38e0bf1a2f200bcf"><div class="ttname"><a href="gurobi__interface_8cc.html#a0728f23c9a47655d38e0bf1a2f200bcf">model</a></div><div class="ttdeci">GRBmodel * model</div><div class="ttdef"><b>Definition:</b> <a href="gurobi__interface_8cc_source.html#l00195">gurobi_interface.cc:195</a></div></div>
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<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a935644a2da13a1ac84cb06649b840283"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a935644a2da13a1ac84cb06649b840283">operations_research::sat::ProbingOptions::use_tree_look</a></div><div class="ttdeci">bool use_tree_look</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00131">probing.h:131</a></div></div>
<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a19601d926c1322ba3e11da2a386397dd"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a19601d926c1322ba3e11da2a386397dd">operations_research::sat::ProbingOptions::use_queue</a></div><div class="ttdeci">bool use_queue</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00137">probing.h:137</a></div></div>
<div class="ttc" id="astructoperations__research_1_1sat_1_1ProbingOptions_html_a9d4ed6726cbb0ec29c0d62faec4b6405"><div class="ttname"><a href="structoperations__research_1_1sat_1_1ProbingOptions.html#a9d4ed6726cbb0ec29c0d62faec4b6405">operations_research::sat::ProbingOptions::extract_binary_clauses</a></div><div class="ttdeci">bool extract_binary_clauses</div><div class="ttdef"><b>Definition:</b> <a href="probing_8h_source.html#l00124">probing.h:124</a></div></div>
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