[Persistence Matrix] replacing static_cast(-1) by method

src/Persistence_matrix/concept/PersistenceMatrixColumn.h

@@ -242,18 +242,19 @@ class PersistenceMatrixColumn :
 
   /**
    * @brief Reorders the column with the given map of row indices. Also changes the column index stored in the
-   * entries if row access is enabled and @p columnIndex is not -1.
+   * entries if row access is enabled and @p columnIndex is not the @ref Matrix::get_null_value "null index".
    *
    * Only useful for @ref basematrix "base" and @ref boundarymatrix "boundary matrices" using lazy swaps.
    * 
    * @tparam Row_index_map Map with an %at() method.
    * @param valueMap Map such that `valueMap.at(i)` indicates the new row index of the entry
    * at current row index `i`.
-   * @param columnIndex New @ref MatIdx column index of the column. If -1, the index does not change. Ignored if
-   * the row access is not enabled. Default value: -1.
+   * @param columnIndex New @ref MatIdx column index of the column. If @ref Matrix::get_null_value "null index",
+   * the index does not change. Ignored if the row access is not enabled.
+   * Default value: @ref Matrix::get_null_value "null index".
    */
   template <class Row_index_map>
-  void reorder(const Row_index_map& valueMap, [[maybe_unused]] Index columnIndex = -1);
+  void reorder(const Row_index_map& valueMap, [[maybe_unused]] Index columnIndex = Matrix::get_null_value<Index>());
   /**
    * @brief Zeros/empties the column.
    * 
@@ -275,11 +276,12 @@ class PersistenceMatrixColumn :
   void clear(ID_index rowIndex);
 
   /**
-   * @brief Returns the row index of the pivot. If the column does not have a pivot, returns -1.
+   * @brief Returns the row index of the pivot. If the column does not have a pivot,
+   * returns @ref Matrix::get_null_value "null index".
    *
    * Only useful for @ref boundarymatrix "boundary" and @ref chainmatrix "chain matrices".
    * 
-   * @return Row index of the pivot or -1.
+   * @return Row index of the pivot or @ref Matrix::get_null_value "null index".
    */
   ID_index get_pivot();
   /**
@@ -429,7 +431,7 @@ class PersistenceMatrixColumn :
   /**
    * @brief Adds a copy of the given entry at the end of the column. It is therefore assumed that the row index
    * of the entry is higher than the current pivot of the column. Not available for @ref chainmatrix "chain matrices"
-   * and is only needed for @ref rumatrix "RU matrices".
+   * and is only needed for @ref boundarymatrix "RU matrices".
    * 
    * @param entry Entry to push back.
    */

src/Persistence_matrix/include/gudhi/Matrix.h

@@ -162,7 +162,15 @@ class Matrix {
    */
   using Element = typename Field_operators::Element;
   using Characteristic = typename Field_operators::Characteristic;
-
+
+  /**
+   * @brief Returns value from a type when not set.
+   */
+  template <typename T>
+  static constexpr const T get_null_value() {
+    return -1;
+  }
+
   /**
    * @brief Type for a bar in the computed barcode. Stores the birth, death and dimension of the bar.
    */
@@ -367,7 +375,7 @@ class Matrix {
     //purposely triggers operators() instead of operators(characteristic) as the "dummy" values for the different
     //operators can be different from -1.
     Column_zp_settings(Characteristic characteristic) : operators(), entryConstructor() {
-      if (characteristic != static_cast<Characteristic>(-1)) operators.set_characteristic(characteristic);
+      if (characteristic != get_null_value<Characteristic>()) operators.set_characteristic(characteristic);
     }
     Column_zp_settings(const Column_zp_settings& toCopy)
         : operators(toCopy.operators.get_characteristic()), entryConstructor() {}
@@ -592,7 +600,7 @@ class Matrix {
    * @ref set_characteristic before calling for the first time a method needing it. Ignored if
    * @ref PersistenceMatrixOptions::is_z2 is true.
    */
-  Matrix(unsigned int numberOfColumns, Characteristic characteristic = static_cast<Characteristic>(-1));
+  Matrix(unsigned int numberOfColumns, Characteristic characteristic = Matrix::get_null_value<Characteristic>());
   /**
    * @brief Constructs a new empty matrix with the given comparator functions. Only available when those comparators
    * are necessary.
@@ -671,7 +679,7 @@ class Matrix {
   Matrix(unsigned int numberOfColumns, 
          const std::function<bool(Pos_index,Pos_index)>& birthComparator,
          const std::function<bool(Pos_index,Pos_index)>& deathComparator, 
-         Characteristic characteristic = static_cast<Characteristic>(-1));
+         Characteristic characteristic = Matrix::get_null_value<Characteristic>());
   /**
    * @brief Copy constructor.
    * 
@@ -765,7 +773,7 @@ class Matrix {
    * chains used to reduce the boundary. Otherwise, nothing.
    */
   template <class Boundary_range = Boundary>
-  Insertion_return insert_boundary(const Boundary_range& boundary, Dimension dim = -1);
+  Insertion_return insert_boundary(const Boundary_range& boundary, Dimension dim = Matrix::get_null_value<Dimension>());
   /**
    * @brief Only available for @ref mp_matrices "non-basic matrices".
    * It does the same as the other version, but allows the boundary cells to be identified without restrictions
@@ -787,7 +795,8 @@ class Matrix {
    * chains used to reduce the boundary. Otherwise, nothing.
    */
   template <class Boundary_range = Boundary>
-  Insertion_return insert_boundary(ID_index cellIndex, const Boundary_range& boundary, Dimension dim = -1);
+  Insertion_return insert_boundary(ID_index cellIndex, const Boundary_range& boundary,
+                                   Dimension dim = Matrix::get_null_value<Dimension>());
 
   /**
    * @brief Returns the column at the given @ref MatIdx index.
@@ -1510,7 +1519,7 @@ template <class PersistenceMatrixOptions>
 inline void Matrix<PersistenceMatrixOptions>::set_characteristic(Characteristic characteristic) 
 {
   if constexpr (!PersistenceMatrixOptions::is_z2) {
-    if (colSettings_->operators.get_characteristic() != static_cast<Characteristic>(-1)) {
+    if (colSettings_->operators.get_characteristic() != get_null_value<Characteristic>()) {
       std::cerr << "Warning: Characteristic already initialised. Changing it could lead to incoherences in the matrix "
                    "as the modulo was already applied to values in existing columns.";
     }
@@ -1524,7 +1533,7 @@ template <class Container>
 inline void Matrix<PersistenceMatrixOptions>::insert_column(const Container& column) 
 {
   if constexpr (!PersistenceMatrixOptions::is_z2){
-    GUDHI_CHECK(colSettings_->operators.get_characteristic() != static_cast<Characteristic>(-1),
+    GUDHI_CHECK(colSettings_->operators.get_characteristic() != get_null_value<Characteristic>(),
                 std::logic_error("Matrix::insert_column - Columns cannot be initialized if the coefficient field "
                                  "characteristic is not specified."));
   }
@@ -1540,7 +1549,7 @@ template <class Container>
 inline void Matrix<PersistenceMatrixOptions>::insert_column(const Container& column, Index columnIndex) 
 {
   if constexpr (!PersistenceMatrixOptions::is_z2){
-    GUDHI_CHECK(colSettings_->operators.get_characteristic() != static_cast<Characteristic>(-1),
+    GUDHI_CHECK(colSettings_->operators.get_characteristic() != get_null_value<Characteristic>(),
                 std::logic_error("Matrix::insert_column - Columns cannot be initialized if the coefficient field "
                                  "characteristic is not specified."));
   }
@@ -1558,7 +1567,7 @@ inline typename Matrix<PersistenceMatrixOptions>::Insertion_return
 Matrix<PersistenceMatrixOptions>::insert_boundary(const Boundary_range& boundary, Dimension dim)
 {
   if constexpr (!PersistenceMatrixOptions::is_z2){
-    GUDHI_CHECK(colSettings_->operators.get_characteristic() != static_cast<Characteristic>(-1),
+    GUDHI_CHECK(colSettings_->operators.get_characteristic() != get_null_value<Characteristic>(),
                 std::logic_error("Matrix::insert_boundary - Columns cannot be initialized if the coefficient field "
                                  "characteristic is not specified."));
   }
@@ -1578,7 +1587,7 @@ Matrix<PersistenceMatrixOptions>::insert_boundary(ID_index cellIndex,
                                                   Dimension dim)
 {
   if constexpr (!PersistenceMatrixOptions::is_z2){
-    GUDHI_CHECK(colSettings_->operators.get_characteristic() != static_cast<Characteristic>(-1),
+    GUDHI_CHECK(colSettings_->operators.get_characteristic() != get_null_value<Characteristic>(),
                 std::logic_error("Matrix::insert_boundary - Columns cannot be initialized if the coefficient field "
                                  "characteristic is not specified."));
   }

src/Persistence_matrix/include/gudhi/Persistence_matrix/Base_matrix.h

@@ -133,7 +133,8 @@ class Base_matrix : public Master_matrix::template Base_swap_option<Base_matrix<
    * @param dim Ignored.
    */
   template <class Boundary_range>
-  void insert_boundary(const Boundary_range& boundary, Dimension dim = -1);
+  void insert_boundary(const Boundary_range& boundary,
+                       Dimension dim = Master_matrix::template get_null_value<Dimension>());
   /**
    * @brief Returns the column at the given @ref MatIdx index.
    * The type of the column depends on the choosen options, see @ref PersistenceMatrixOptions::column_type.
@@ -438,7 +439,7 @@ template <class Master_matrix>
 template <class Boundary_range>
 inline void Base_matrix<Master_matrix>::insert_boundary(const Boundary_range& boundary, Dimension dim) 
 {
-  if (dim == -1) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
+  if (dim == Master_matrix::template get_null_value<Dimension>()) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
   //TODO: dim not actually stored right now, so either get rid of it or store it again
   _insert(boundary, nextInsertIndex_++, dim);
 }

src/Persistence_matrix/include/gudhi/Persistence_matrix/Base_matrix_with_column_compression.h

@@ -180,7 +180,8 @@ class Base_matrix_with_column_compression : protected Master_matrix::Matrix_row_
    * @param dim Ignored.
    */
   template <class Boundary_range>
-  void insert_boundary(const Boundary_range& boundary, Dimension dim = -1);
+  void insert_boundary(const Boundary_range& boundary,
+                       Dimension dim = Master_matrix::template get_null_value<Dimension>());
   /**
    * @brief Returns the column at the given @ref MatIdx index.
    * The type of the column depends on the choosen options, see @ref PersistenceMatrixOptions::column_type.
@@ -450,7 +451,7 @@ inline void Base_matrix_with_column_compression<Master_matrix>::insert_boundary(
   // handles a dimension which is not actually stored.
   // TODO: verify if this is not a problem for the cohomology algorithm and if yes,
   // change how Column_dimension_option is choosen.
-  if (dim == -1) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
+  if (dim == Master_matrix::template get_null_value<Dimension>()) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
 
   if constexpr (Master_matrix::Option_list::has_row_access && !Master_matrix::Option_list::has_removable_rows) {
     if (boundary.begin() != boundary.end()) {

src/Persistence_matrix/include/gudhi/Persistence_matrix/Boundary_matrix.h

@@ -141,7 +141,8 @@ class Boundary_matrix : public Master_matrix::Matrix_dimension_option,
    * @return The @ref MatIdx index of the inserted boundary.
    */
   template <class Boundary_range = Boundary>
-  Index insert_boundary(const Boundary_range& boundary, Dimension dim = -1);
+  Index insert_boundary(const Boundary_range& boundary,
+                        Dimension dim = Master_matrix::template get_null_value<Dimension>());
   /**
    * @brief It does the same as the other version, but allows the boundary cells to be identified without restrictions
    * except that all IDs have to be strictly increasing in the order of filtration. Note that you should avoid then
@@ -161,7 +162,8 @@ class Boundary_matrix : public Master_matrix::Matrix_dimension_option,
    * @return The @ref MatIdx index of the inserted boundary.
    */
   template <class Boundary_range = Boundary>
-  Index insert_boundary(ID_index cellIndex, const Boundary_range& boundary, Dimension dim = -1);
+  Index insert_boundary(ID_index cellIndex, const Boundary_range& boundary,
+                        Dimension dim = Master_matrix::template get_null_value<Dimension>());
   /**
    * @brief Returns the column at the given @ref MatIdx index.
    * The type of the column depends on the choosen options, see @ref PersistenceMatrixOptions::column_type.
@@ -384,7 +386,7 @@ class Boundary_matrix : public Master_matrix::Matrix_dimension_option,
 
 template <class Master_matrix>
 inline Boundary_matrix<Master_matrix>::Boundary_matrix(Column_settings* colSettings)
-    : Dim_opt(-1),
+    : Dim_opt(Master_matrix::template get_null_value<Dimension>()),
       Swap_opt(),
       Pair_opt(),
       RA_opt(),
@@ -396,7 +398,7 @@ template <class Master_matrix>
 template <class Boundary_range>
 inline Boundary_matrix<Master_matrix>::Boundary_matrix(const std::vector<Boundary_range>& orderedBoundaries,
                                                        Column_settings* colSettings)
-    : Dim_opt(-1),
+    : Dim_opt(Master_matrix::template get_null_value<Dimension>()),
       Swap_opt(orderedBoundaries.size()),
       Pair_opt(),
       RA_opt(orderedBoundaries.size()),
@@ -413,7 +415,7 @@ inline Boundary_matrix<Master_matrix>::Boundary_matrix(const std::vector<Boundar
 template <class Master_matrix>
 inline Boundary_matrix<Master_matrix>::Boundary_matrix(unsigned int numberOfColumns, 
                                                        Column_settings* colSettings)
-    : Dim_opt(-1),
+    : Dim_opt(Master_matrix::template get_null_value<Dimension>()),
       Swap_opt(numberOfColumns),
       Pair_opt(),
       RA_opt(numberOfColumns),
@@ -471,7 +473,7 @@ template <class Boundary_range>
 inline typename Boundary_matrix<Master_matrix>::Index Boundary_matrix<Master_matrix>::insert_boundary(
     ID_index cellIndex, const Boundary_range& boundary, Dimension dim) 
 {
-  if (dim == -1) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
+  if (dim == Master_matrix::template get_null_value<Dimension>()) dim = boundary.size() == 0 ? 0 : boundary.size() - 1;
 
   _orderRowsIfNecessary();
 
@@ -543,7 +545,7 @@ inline typename Boundary_matrix<Master_matrix>::Index Boundary_matrix<Master_mat
   static_assert(Master_matrix::Option_list::has_removable_columns,
                 "'remove_last' is not implemented for the chosen options.");
 
-  if (nextInsertIndex_ == 0) return -1;  // empty matrix
+  if (nextInsertIndex_ == 0) return Master_matrix::template get_null_value<Index>();  // empty matrix
   --nextInsertIndex_;
 
   //updates dimension max
@@ -558,7 +560,7 @@ inline typename Boundary_matrix<Master_matrix>::Index Boundary_matrix<Master_mat
     pivot = it->second.get_pivot();
     if constexpr (activeSwapOption) {
       // if the removed column is positive, the pivot won't change value
-      if (Swap_opt::rowSwapped_ && pivot != static_cast<ID_index>(-1)) {
+      if (Swap_opt::rowSwapped_ && pivot != Master_matrix::template get_null_value<ID_index>()) {
         Swap_opt::_orderRows();
         pivot = it->second.get_pivot();
       }
@@ -568,7 +570,7 @@ inline typename Boundary_matrix<Master_matrix>::Index Boundary_matrix<Master_mat
     pivot = matrix_[nextInsertIndex_].get_pivot();
     if constexpr (activeSwapOption) {
       // if the removed column is positive, the pivot won't change value
-      if (Swap_opt::rowSwapped_ && pivot != static_cast<ID_index>(-1)) {
+      if (Swap_opt::rowSwapped_ && pivot != Master_matrix::template get_null_value<ID_index>()) {
         Swap_opt::_orderRows();
         pivot = matrix_[nextInsertIndex_].get_pivot();
       }