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…d documentation

include/libsemigroups/sims.hpp

@@ -1343,7 +1343,6 @@ namespace libsemigroups {
     //! Default constructor
     Sims1() = default;
 
-    // TODO(0) (doc)
     using SimsBase::init;
 
     //! \brief Construct from a presentation.
@@ -1429,6 +1428,19 @@ namespace libsemigroups {
     }
 
 #ifdef PARSED_BY_DOXYGEN
+    //! \brief Reinitialize an existing Sims1 object.
+    //!
+    //! This function puts a Sims1 object back into the same state as if
+    //! it had been newly default constructed.
+    //!
+    //! \parameters (None)
+    //!
+    //! \returns A reference to \c this.
+    //!
+    //! \exception
+    //! \no_libsemigroups_except
+    Sims1& init();
+
     //! \brief Returns the number of one-sided congruences with up to a given
     //! number of classes.
     //!
@@ -1619,6 +1631,8 @@ namespace libsemigroups {
     //! The \ref WordGraph::size_type of the associated WordGraph objects.
     using size_type = word_graph_type::size_type;
 
+    using SimsBase::init;
+
     //! Default constructor.
     Sims2() = default;
     //! Default copy constructor.
@@ -1632,22 +1646,6 @@ namespace libsemigroups {
 
     ~Sims2() = default;
 
-    //! \brief Reinitialize an existing Sims2 object.
-    //!
-    //! This function puts a Sims2 object back into the same state as if
-    //! it had been newly default constructed.
-    //!
-    //! \parameters (None)
-    //!
-    //! \returns A reference to \c this.
-    //!
-    //! \exception
-    //! \no_libsemigroups_except
-    Sims2& init() {
-      SimsSettings<Sims2>::init();
-      return *this;
-    }
-
     //! \copydoc Sims1::Sims1(Presentation<Word> const&)
     template <typename Word>
     explicit Sims2(Presentation<Word> const& p) : Sims2() {
@@ -1696,6 +1694,19 @@ namespace libsemigroups {
     }
 
 #ifdef PARSED_BY_DOXYGEN
+    //! \brief Reinitialize an existing Sims2 object.
+    //!
+    //! This function puts a Sims2 object back into the same state as if
+    //! it had been newly default constructed.
+    //!
+    //! \parameters (None)
+    //!
+    //! \returns A reference to \c this.
+    //!
+    //! \exception
+    //! \no_libsemigroups_except
+    Sims2& init();
+
     //! \copydoc Sims1::number_of_congruences
     uint64_t number_of_congruences(size_t n);
 
@@ -2093,7 +2104,6 @@ namespace libsemigroups {
     // Right Congruence Generating Pairs (rcgp)
     class const_rcgp_iterator {
      public:
-      // TODO(0) (doc)
       using size_type = typename std::vector<relation_type>::size_type;
       using difference_type =
           typename std::vector<relation_type>::difference_type;
@@ -2990,7 +3000,7 @@ namespace libsemigroups {
     }
 
     //! \brief Reinitialize an existing SimsRefinerIdeals object from a
-    //! presentation.
+    //! word_type presentation.
     //!
     //! This function puts an object back into the same state as if it had
     //! been newly constructed from the presentation \p p.
@@ -3009,7 +3019,7 @@ namespace libsemigroups {
     //! presentation \p p. If this is not the case then th pruner may not
     //! terminate on certain inputs.
     //!
-    //! \sa presentation(Presentation<std::string> const&)
+    //! \sa presentation(Presentation<word_type> const&)
     SimsRefinerIdeals& init(Presentation<word_type> const& p) {
       _presentation = p;
       _knuth_bendices[0].init(congruence_kind::twosided, _presentation).run();
@@ -3019,6 +3029,27 @@ namespace libsemigroups {
       return *this;
     }
 
+    //! \brief Reinitialize an existing SimsRefinerIdeals object from a
+    //! std::string presentation.
+    //!
+    //! This function puts an object back into the same state as if it had
+    //! been newly constructed from the presentation \p p.
+    //!
+    //! \returns A reference to \c *this.
+    //!
+    //! \throws LibsemigroupsException if `p` is not valid
+    //! \throws LibsemigroupsException if `p` has 0-generators and 0-relations.
+    //!
+    //! \warning This function has no exception guarantee, the object will be
+    //! in the same state as if it was default constructed if an exception is
+    //! thrown.
+    //!
+    //! \warning
+    //! This method assumes that KnuthBendix terminates on the input
+    //! presentation \p p. If this is not the case then th pruner may not
+    //! terminate on certain inputs.
+    //!
+    //! \sa presentation(Presentation<std::string> const&)
     SimsRefinerIdeals& init(Presentation<std::string> const& p) {
       _presentation = to_presentation<word_type>(p);
       _knuth_bendices[0].init(congruence_kind::twosided, _presentation).run();

include/libsemigroups/sims.tpp

@@ -171,7 +171,7 @@ namespace libsemigroups {
           // TODO(2) avoid the copy here
           copy.induced_subgraph_no_checks(static_cast<Node>(0),
                                           wg.number_of_active_nodes());
-          tc.init(congruence_kind::onesided, copy);
+          tc.init(congruence_kind::onesided, p, copy);
           todd_coxeter::add_generating_pair(tc, wx, wy);
           // LIBSEMIGROUPS_ASSERT(tc.word_graph().number_of_nodes()
           //                      == wg.number_of_active_nodes());

include/libsemigroups/todd-coxeter.hpp

@@ -755,6 +755,19 @@ namespace libsemigroups {
     //! \no_libsemigroups_except
     // TODO(1) a to_todd_coxeter variant that throws if wg is not valid
     // see below
+    // TODO(1) Document the requirement that the word graph has every node
+    // reachable from 0 if knd == congruence_kind::onesided. Otherwise can't
+    // really perform one-sided ToddCoxeter since we can't know how the
+    // generators map onto nodes of the word graph. If we assume the underlying
+    // presentation and word graph correspond to a monoid then this can be done
+    // if we also assume by convention that the 0 node of the word graph
+    // corresponds to the identity. According to JDM this is what is done and so
+    // it should be reflected in the documentation.
+    // TODO(2) Fix issue where contains_empty_word is false when initializing
+    // from a monoid word graph. Note that we do not want to add an extra
+    // identity node in this case as that's the wrong behaviour. Instead we
+    // would like to somehow link the 0 vertex to the identity of the
+    // presentation.
     template <typename Node>
     ToddCoxeter(congruence_kind knd, WordGraph<Node> const& wg)
         : ToddCoxeter() {
@@ -885,6 +898,9 @@ namespace libsemigroups {
     // Used in Sims
     // TODO(0) could this and the next function be removed, and replaced with
     // something else?
+    // NOTE (reiniscirpons): It potentially could, but before doing so, some
+    // issues with initializing congruence_kind::onesided ToddCoxeter from a
+    // word graph should be fixed otherwise this will cause issues in Sims
     template <typename Node>
     ToddCoxeter(congruence_kind                knd,
                 Presentation<word_type> const& p,