[API] The alignment configuration for the band changed to seqan3::align_cfg::band_fixed_size

CHANGELOG.md

@@ -64,6 +64,16 @@ Note that 3.1.0 will be the first API stable release and interfaces in this rele
 
 ## API changes
 
+### Alignment
+
+* The alignment configuration elements were refactored:
+  * The option `seqan3::align_cfg::band` is now renamed to `seqan3::align_cfg::band_fixed_size` and directly initialised
+    with a `seqan3::align_cfg::lower_diagonal` and `seqan3::align_cfg::upper_diagonal` instead of `seqan3::static_band`.
+    It also directly exposes the lower_diagonal and upper_diagonal as public members
+    ([\#1873](https://github.com/seqan/seqan3/pull/1873)).
+
+### Core
+
 * In accordance with the standard, the following concepts are renamed:
   * `default_constructible` to `default_initializable`
   * `readable` to `indirectly_readable`

doc/tutorial/pairwise_alignment/configurations.cpp

@@ -20,7 +20,6 @@
 //! [include_result]
 
 //! [include_band]
-#include <seqan3/alignment/band/static_band.hpp>
 #include <seqan3/alignment/configuration/align_config_band.hpp>
 //! [include_band]
 
@@ -92,7 +91,8 @@ auto cfg = seqan3::align_cfg::result{seqan3::with_score};
 //! [band]
 
 // Configure a banded alignment.
-auto cfg = seqan3::align_cfg::band{seqan3::static_band{seqan3::lower_bound{-4}, seqan3::upper_bound{4}}};
+auto cfg = seqan3::align_cfg::band_fixed_size{seqan3::align_cfg::lower_diagonal{-4},
+                                              seqan3::align_cfg::upper_diagonal{4}};
 //! [band]
 (void) cfg;
 }

doc/tutorial/pairwise_alignment/index.md

@@ -267,14 +267,14 @@ In many situations it is not necessary to compute the entire alignment matrix bu
 positive impacts on the performance. To limit the computation space the alignment matrix can be bounded by a band.
 Thus, only the alignment is computed that fits in this band. Note that this must not be the optimal alignment but in
 many cases we can give a rough bound on how similar the sequences will be and therefor use the banded alignment.
-To do so, you can use a seqan3::static_band. It will be initialised with a seqan3::lower_bound and a
-seqan3::upper_bound. To configure the banded alignment you need to use the seqan3::align_cfg::band configuration.
+To do so, you can configure the alignment using the seqan3::align_cfg::band_fixed_size option. This configuration
+element will be initialised with a seqan3::align_cfg::lower_diagonal and seqan3::align_cfg::upper_diagonal.
 
 \snippet doc/tutorial/pairwise_alignment/configurations.cpp include_band
 \snippet doc/tutorial/pairwise_alignment/configurations.cpp band
 
 \assignment{Assignment 5}
-Use the example from assignment 4 and compute it in a band with lower bound set to `-3` and upper bound set to `8`.
+Use the example from assignment 4 and compute it in a band with lower diagonal set to `-3` and upper diagonal set to `8`.
 How does the result change?
 
 \endassignment

doc/tutorial/pairwise_alignment/pairwise_alignment_solution_5.cpp

@@ -1,6 +1,5 @@
 #include <utility>
 
-#include <seqan3/alignment/band/static_band.hpp>
 #include <seqan3/alignment/pairwise/align_pairwise.hpp>
 #include <seqan3/alignment/scoring/nucleotide_scoring_scheme.hpp>
 #include <seqan3/alphabet/nucleotide/dna4.hpp>
@@ -20,7 +19,8 @@ int main()
                   seqan3::align_cfg::gap{seqan3::gap_scheme{seqan3::gap_score{-4}}} |
                   seqan3::align_cfg::aligned_ends{seqan3::free_ends_all} |
                   seqan3::align_cfg::result{seqan3::with_alignment} |
-                  seqan3::align_cfg::band{seqan3::static_band{seqan3::lower_bound{-3}, seqan3::upper_bound{8}}};
+                  seqan3::align_cfg::band_fixed_size{seqan3::align_cfg::lower_diagonal{-3},
+                                                     seqan3::align_cfg::upper_diagonal{8}};
 
     for (auto const & res : seqan3::align_pairwise(std::tie(seq1, seq2), config))
     {

include/seqan3/alignment/all.hpp

@@ -81,7 +81,7 @@
  * | **Config**                                              | **0** | **1** | **2** | **3** | **4** | **5** | **6** | **7** | **8** | **9** |
  * | --------------------------------------------------------|-------|-------|-------|-------|-------|-------|-------|-------|-------|-------|
  * | \ref seqan3::align_cfg::aligned_ends "0: Aligned ends"  |   ❌   |   ✅   |  ✅    |  ❌    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |
- * | \ref seqan3::align_cfg::band "1: Band"                  |       |   ❌   |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |
+ * | \ref seqan3::align_cfg::band_fixed_size "1: Band"       |       |   ❌   |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |
  * | \ref seqan3::align_cfg::gap "2: Gap scheme"             |       |       |   ❌   |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |
  * | \ref seqan3::global_alignment "3: Global alignment"     |       |       |       |  ❌    |  ❌    |  ✅    |  ✅    |  ✅    |  ✅    |  ✅    |
  * | \ref seqan3::local_alignment "4: Local alignment"       |       |       |       |       |  ❌    |  ❌    |  ✅    |  ✅    |  ✅    |  ✅    |
@@ -171,12 +171,12 @@
  *
  * SeqAn offers the computation of banded alignments to reduce the running time of the algorithm. This can be
  * helpful if the region in which the optimal alignment exists is known a priori. To specify the banded alignment
- * the developer can use the seqan3::align_cfg::band option initialised with a seqan3::static_band.
- * The seqan3::static_band is constructed with a lower bound and an upper bound. The upper bound must always be greater
- * than or equal to the lower bound. To position the band, imagine a rectangle where the first sequence is written on
- * top and the second sequence along the left vertical side. A negative bound implies a start of the band within the
- * vertical part while a positive bound implies a start within the top part of this rectangle at the respective
- * position.
+ * the developer can use the seqan3::align_cfg::band_fixed_size option.
+ * This band configuration is initialised with a seqan3::align_cfg::lower_diagonal and an
+ * seqan3::align_cfg::upper_diagonal. The upper diagonal must always be greater than or equal to the lower diagonal.
+ * To choose the correct band parameters, imagine a matrix with the first sequence written on top and the second sequence
+ * along the left vertical side. A negative value reflects a start of the diagonal within the vertical part while a
+ * positive value implies a start within the top part of this matrix at the respective position.
  *
  * ## Global and local alignments
  *

include/seqan3/alignment/configuration/align_config_band.hpp

@@ -14,51 +14,104 @@
 #pragma once
 
 #include <seqan3/alignment/configuration/detail.hpp>
-#include <seqan3/alignment/band/static_band.hpp>
+#include <seqan3/alignment/exception.hpp>
 #include <seqan3/core/algorithm/pipeable_config_element.hpp>
+#include <seqan3/core/detail/empty_type.hpp>
+#include <seqan3/core/detail/strong_type.hpp>
 
 namespace seqan3::align_cfg
 {
 
-/*!\brief Configuration element for setting the band.
+/*!\brief A strong type representing the lower diagonal of the seqan3::align_cfg::band_fixed_size.
+ * \ingroup alignment_configuration
+ */
+struct lower_diagonal : public seqan3::detail::strong_type<int32_t, lower_diagonal>
+{
+    //!\brief The type of the strong type base class.
+    using base_t = seqan3::detail::strong_type<int32_t, lower_diagonal>;
+    // Import the base class constructors
+    using base_t::base_t;
+};
+
+/*!\brief A strong type representing the upper diagonal of the seqan3::align_cfg::band_fixed_size.
+ * \ingroup alignment_configuration
+ */
+struct upper_diagonal : public seqan3::detail::strong_type<int32_t, upper_diagonal>
+{
+    //!\brief The type of the strong type base class.
+    using base_t = seqan3::detail::strong_type<int32_t, upper_diagonal>;
+    // Import the base class constructors
+    using base_t::base_t;
+};
+
+/*!\brief Configuration element for setting a fixed size band.
  * \ingroup alignment_configuration
- *
- * \tparam band_t The type of the band.
  *
  * \details
  *
- * Configures the banded alignment algorithm. Currently only seqan3::static_band is allowed as argument.
- * If no band is configured for the alignment algorithm the full alignment matrix will be computed.
- * Before executing the algorithm the band is tested for valid settings, e.g. that the upper bound is not smaller than
- * the lower bound, or the band is not shifted out of the alignment matrix. If an invalid setting is detected, a
- * seqan3::invalid_alignment_configuration exception will be thrown.
+ * Configures the banded alignment algorithm. Currently only a fixed size band is allowed.
+ * The band is given in form of a seqan3::align_cfg::lower_diagonal and a seqan3::align_cfg::upper_diagonal.
+ * A diagonal represents the cells in the alignment matrix that are not crossed by the alignment either downwards by
+ * the lower diagonal or rightwards by the upper diagonal. Thus any computed alignment will be inside the area defined
+ * by the lower and the upper diagonal.
+ *
+ * If this configuration is default constructed or not set during the algorithm configuration the full alignment
+ * matrix will be computed.
+ *
+ * During the construction of this configuration element or before the execution of the alignment algorithm the
+ * band configuration is validated. If the user provided an invalid band, e.g. the upper diagonal is smaller than
+ * the lower diagonal, the alignment matrix would be ill configured such that the requested alignment method cannot
+ * be computed (because the global alignment requires the first cell and the last cell of the matrix to be reachable),
+ * then a seqan3::invalid_alignment_configuration will be thrown.
  *
  * ### Example
  *
  * \include test/snippet/alignment/configuration/align_cfg_band_example.cpp
  */
-template <typename band_t>
-//!\cond
-    requires std::same_as<band_t, static_band>
-//!\endcond
-struct band : public pipeable_config_element<band<band_t>, band_t>
+class band_fixed_size : public pipeable_config_element<band_fixed_size>
 {
+private:
+    //!\brief The base class type.
+    using base_t = pipeable_config_element<band_fixed_size>;
+
+public:
+    //!\brief The selected lower diagonal. Defaults to `std::%numeric_limits<int32_t>::%lowest()`.
+    seqan3::align_cfg::lower_diagonal lower_diagonal{std::numeric_limits<int32_t>::lowest()};
+    //!\brief The selected upper diagonal. Defaults to `std::%numeric_limits<int32_t>::%max()`.
+    seqan3::align_cfg::upper_diagonal upper_diagonal{std::numeric_limits<int32_t>::max()};
+
+    /*!\name Constructor, destructor and assignment
+     * \{
+     */
+    constexpr band_fixed_size() = default; //!< Defaulted.
+    constexpr band_fixed_size(band_fixed_size const &) = default; //!< Defaulted.
+    constexpr band_fixed_size(band_fixed_size &&) = default; //!< Defaulted.
+    constexpr band_fixed_size & operator=(band_fixed_size const &) = default; //!< Defaulted.
+    constexpr band_fixed_size & operator=(band_fixed_size &&) = default; //!< Defaulted.
+    ~band_fixed_size() = default; //!< Defaulted.
+
+    /*!\brief Initialises the fixed size band by setting the lower and the upper matrix diagonal.
+     *
+     * \param lower_diagonal \copybrief seqan3::align_cfg::band_fixed_size::lower_diagonal
+     * \param upper_diagonal \copybrief seqan3::align_cfg::band_fixed_size::upper_diagonal
+     *
+     * \details
+     *
+     * The lower diagonal represents the lower bound of the banded matrix, i.e. the alignment cannot pass below this
+     * diagonal. Similar, the upper diagonal represents the upper bound of the alignment. During the alignment
+     * configuration and execution the band parameters will be checked and an exception will be thrown in case of
+     * an invalid configuration.
+     */
+    constexpr band_fixed_size(seqan3::align_cfg::lower_diagonal const lower_diagonal,
+                              seqan3::align_cfg::upper_diagonal const upper_diagonal) :
+        lower_diagonal{std::move(lower_diagonal)},
+        upper_diagonal{std::move(upper_diagonal)}
+    {}
+    //!\}
+
     //!\privatesection
     //!\brief Internal id to check for consistent configuration settings.
     static constexpr detail::align_config_id id{detail::align_config_id::band};
 };
 
-/*!\name Type deduction guides
- * \brief Deduces the template parameter from the argument.
- * \relates seqan3::align_cfg::band
- * \{
- */
-/*!
- * \brief Deduces the underlying band type.
- * \tparam band_t The underlying type of the band.
- */
-template <typename band_t>
-band(band_t) -> band<band_t>;
-//!\}
-
-} // namespace seqan3::detail
+} // namespace seqan3::align_cfg

include/seqan3/alignment/configuration/detail.hpp

@@ -25,7 +25,7 @@ enum struct align_config_id : uint8_t
     //!\brief ID for the \ref seqan3::align_cfg::alignment_result_capture "alignment_result_capture" option.
     alignment_result_capture,
     aligned_ends, //!< ID for the \ref seqan3::align_cfg::aligned_ends "aligned_ends" option.
-    band,         //!< ID for the \ref seqan3::align_cfg::band "band" option.
+    band,         //!< ID for the \ref seqan3::align_cfg::band_fixed_size "band" option.
     debug,        //!< ID for the \ref seqan3::align_cfg::debug "debug" option.
     gap,          //!< ID for the \ref seqan3::align_cfg::gap "gap" option.
     global,       //!< ID for the \ref seqan3::global_alignment "global alignment" option.

include/seqan3/alignment/matrix/detail/aligned_sequence_builder.hpp

@@ -16,7 +16,6 @@
 #include <vector>
 
 #include <seqan3/alignment/aligned_sequence/aligned_sequence_concept.hpp>
-#include <seqan3/alignment/band/static_band.hpp>
 #include <seqan3/alignment/matrix/detail/matrix_coordinate.hpp>
 #include <seqan3/alignment/matrix/trace_directions.hpp>
 #include <seqan3/alphabet/gap/gapped.hpp>

include/seqan3/alignment/matrix/detail/alignment_score_matrix_one_column_banded.hpp

@@ -12,7 +12,7 @@
 
 #pragma once
 
-#include <seqan3/alignment/band/static_band.hpp>
+#include <seqan3/alignment/configuration/align_config_band.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_matrix_column_major_range_base.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_score_matrix_one_column_base.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_score_matrix_proxy.hpp>
@@ -99,7 +99,7 @@ class alignment_score_matrix_one_column_banded :
      *
      * \param[in] first          The first range.
      * \param[in] second         The second range.
-     * \param[in] band           The seqan3::static_band in which to calculate the alignment.
+     * \param[in] band           The seqan3::align_cfg::band_fixed_size in which to calculate the alignment.
      * \param[in] initial_value  The value to initialise the matrix with. Default initialised if not specified.
      *
      * \details
@@ -111,14 +111,14 @@ class alignment_score_matrix_one_column_banded :
               std::ranges::forward_range second_sequence_t>
     constexpr alignment_score_matrix_one_column_banded(first_sequence_t && first,
                                                        second_sequence_t && second,
-                                                       static_band const & band,
+                                                       align_cfg::band_fixed_size const & band,
                                                        score_t const initial_value = score_t{})
     {
         matrix_base_t::num_cols = static_cast<size_type>(std::ranges::distance(first) + 1);
         matrix_base_t::num_rows = static_cast<size_type>(std::ranges::distance(second) + 1);
 
-        band_col_index = std::min<int32_t>(std::max<int32_t>(band.upper_bound, 0), matrix_base_t::num_cols - 1);
-        band_row_index = std::min<int32_t>(std::abs(std::min<int32_t>(band.lower_bound, 0)),
+        band_col_index = std::min<int32_t>(std::max<int32_t>(band.upper_diagonal.get(), 0), matrix_base_t::num_cols - 1);
+        band_row_index = std::min<int32_t>(std::abs(std::min<int32_t>(band.lower_diagonal.get(), 0)),
                                            matrix_base_t::num_rows - 1);
 
         band_size = band_col_index + band_row_index + 1;

include/seqan3/alignment/matrix/detail/alignment_trace_matrix_full_banded.hpp

@@ -12,7 +12,7 @@
 
 #pragma once
 
-#include <seqan3/alignment/band/static_band.hpp>
+#include <seqan3/alignment/configuration/align_config_band.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_matrix_column_major_range_base.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_trace_matrix_base.hpp>
 #include <seqan3/alignment/matrix/detail/alignment_trace_matrix_proxy.hpp>
@@ -115,7 +115,7 @@ class alignment_trace_matrix_full_banded :
      *
      * \param[in] first         The first range.
      * \param[in] second        The second range.
-     * \param[in] band          The seqan3::static_band in which to calculate the alignment.
+     * \param[in] band          The seqan3::align_cfg::band_fixed_size in which to calculate the alignment.
      * \param[in] initial_value The value to initialise the matrix with. Default initialised if not specified.
      *
      * \details
@@ -127,14 +127,16 @@ class alignment_trace_matrix_full_banded :
     template <std::ranges::forward_range first_sequence_t, std::ranges::forward_range second_sequence_t>
     constexpr alignment_trace_matrix_full_banded(first_sequence_t && first,
                                                  second_sequence_t && second,
-                                                 static_band const & band,
+                                                 align_cfg::band_fixed_size const & band,
                                                  [[maybe_unused]] trace_t const initial_value = trace_t{})
     {
         matrix_base_t::num_cols = static_cast<size_type>(std::ranges::distance(first) + 1);
         matrix_base_t::num_rows = static_cast<size_type>(std::ranges::distance(second) + 1);
 
-        band_col_index = std::min<int32_t>(std::max<int32_t>(band.upper_bound, 0), matrix_base_t::num_cols - 1);
-        band_row_index = std::min<int32_t>(std::abs(std::min<int32_t>(band.lower_bound, 0)), matrix_base_t::num_rows - 1);
+        band_col_index = std::min<int32_t>(std::max<int32_t>(band.upper_diagonal.get(), 0),
+                                           matrix_base_t::num_cols - 1);
+        band_row_index = std::min<int32_t>(std::abs(std::min<int32_t>(band.lower_diagonal.get(), 0)),
+                                           matrix_base_t::num_rows - 1);
         band_size = band_col_index + band_row_index + 1;
 
         // Reserve one more cell to deal with last cell in the banded column which needs only the diagonal and up cell.