alignment_configurator.hpp

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// SPDX-FileCopyrightText: 2006-2025 Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2025 Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <functional>
#include <tuple>
#include <utility>
#include <vector>
 
#include <seqan3/alignment/configuration/align_config_output.hpp>
#include <seqan3/alignment/configuration/align_config_result_type.hpp>
#include <seqan3/alignment/matrix/detail/alignment_score_matrix_one_column.hpp>
#include <seqan3/alignment/matrix/detail/alignment_score_matrix_one_column_banded.hpp>
#include <seqan3/alignment/matrix/detail/alignment_trace_matrix_full.hpp>
#include <seqan3/alignment/matrix/detail/alignment_trace_matrix_full_banded.hpp>
#include <seqan3/alignment/matrix/detail/combined_score_and_trace_matrix.hpp>
#include <seqan3/alignment/matrix/detail/score_matrix_single_column.hpp>
#include <seqan3/alignment/matrix/detail/trace_matrix_full.hpp>
#include <seqan3/alignment/pairwise/align_result_selector.hpp>
#include <seqan3/alignment/pairwise/alignment_algorithm.hpp>
#include <seqan3/alignment/pairwise/alignment_result.hpp>
#include <seqan3/alignment/pairwise/detail/concept.hpp>
#include <seqan3/alignment/pairwise/detail/pairwise_alignment_algorithm.hpp>
#include <seqan3/alignment/pairwise/detail/pairwise_alignment_algorithm_banded.hpp>
#include <seqan3/alignment/pairwise/detail/policy_affine_gap_recursion.hpp>
#include <seqan3/alignment/pairwise/detail/policy_affine_gap_recursion_banded.hpp>
#include <seqan3/alignment/pairwise/detail/policy_affine_gap_with_trace_recursion.hpp>
#include <seqan3/alignment/pairwise/detail/policy_affine_gap_with_trace_recursion_banded.hpp>
#include <seqan3/alignment/pairwise/detail/policy_alignment_matrix.hpp>
#include <seqan3/alignment/pairwise/detail/policy_alignment_result_builder.hpp>
#include <seqan3/alignment/pairwise/detail/policy_optimum_tracker.hpp>
#include <seqan3/alignment/pairwise/detail/policy_optimum_tracker_simd.hpp>
#include <seqan3/alignment/pairwise/detail/policy_scoring_scheme.hpp>
#include <seqan3/alignment/pairwise/detail/type_traits.hpp>
#include <seqan3/alignment/pairwise/edit_distance_algorithm.hpp>
#include <seqan3/alignment/pairwise/policy/affine_gap_init_policy.hpp>
#include <seqan3/alignment/pairwise/policy/affine_gap_policy.hpp>
#include <seqan3/alignment/pairwise/policy/alignment_matrix_policy.hpp>
#include <seqan3/alignment/pairwise/policy/find_optimum_policy.hpp>
#include <seqan3/alignment/pairwise/policy/scoring_scheme_policy.hpp>
#include <seqan3/alignment/pairwise/policy/simd_affine_gap_policy.hpp>
#include <seqan3/alignment/pairwise/policy/simd_find_optimum_policy.hpp>
#include <seqan3/alignment/scoring/aminoacid_scoring_scheme.hpp>
#include <seqan3/alignment/scoring/detail/simd_match_mismatch_scoring_scheme.hpp>
#include <seqan3/alignment/scoring/detail/simd_matrix_scoring_scheme.hpp>
#include <seqan3/alignment/scoring/nucleotide_scoring_scheme.hpp>
#include <seqan3/core/detail/deferred_crtp_base.hpp>
#include <seqan3/core/detail/template_inspection.hpp>
#include <seqan3/utility/simd/simd.hpp>
#include <seqan3/utility/tuple/concept.hpp>
#include <seqan3/utility/type_traits/lazy_conditional.hpp>
#include <seqan3/utility/views/type_reduce.hpp>
#include <seqan3/utility/views/zip.hpp>
 
namespace seqan3::detail
{
 
template <typename range_type, typename alignment_config_type>
struct alignment_contract
{
private:
    using unref_range_type = std::remove_reference_t<range_type>;
    using first_seq_t = std::tuple_element_t<0, std::ranges::range_value_t<unref_range_type>>;
    using second_seq_t = std::tuple_element_t<1, std::ranges::range_value_t<unref_range_type>>;
 
public:
    static constexpr bool expects_tuple_like_value_type()
    {
        return tuple_like<alignment_config_type>
            && std::tuple_size_v<std::ranges::range_value_t<unref_range_type>> == 2;
    }
 
    static constexpr bool expects_valid_scoring_scheme()
    {
        if constexpr (alignment_config_type::template exists<align_cfg::scoring_scheme>())
        {
            using scoring_type = std::remove_reference_t<
                decltype(get<align_cfg::scoring_scheme>(std::declval<alignment_config_type>()).scheme)>;
            return static_cast<bool>(scoring_scheme_for<scoring_type,
                                                        std::ranges::range_value_t<first_seq_t>,
                                                        std::ranges::range_value_t<second_seq_t>>);
        }
        else
        {
            return false;
        }
    }
 
    static constexpr bool expects_alignment_configuration()
    {
        bool const is_global = alignment_config_type::template exists<seqan3::align_cfg::method_global>();
        bool const is_local = alignment_config_type::template exists<seqan3::align_cfg::method_local>();
 
        return (is_global || is_local);
    }
};
 
struct alignment_configurator
{
private:
    template <typename traits_t>
    struct select_matrix_policy
    {
    private:
        static constexpr bool only_coordinates =
            !(traits_t::compute_begin_positions || traits_t::compute_sequence_alignment);
 
        using score_matrix_t =
            std::conditional_t<traits_t::is_banded,
                               alignment_score_matrix_one_column_banded<typename traits_t::score_type>,
                               alignment_score_matrix_one_column<typename traits_t::score_type>>;
        using trace_matrix_t =
            std::conditional_t<traits_t::is_banded,
                               alignment_trace_matrix_full_banded<typename traits_t::trace_type, only_coordinates>,
                               alignment_trace_matrix_full<typename traits_t::trace_type, only_coordinates>>;
 
    public:
        using type = deferred_crtp_base<alignment_matrix_policy, score_matrix_t, trace_matrix_t>;
    };
 
    template <typename traits_t>
    struct select_gap_policy
    {
    private:
        using score_t = typename traits_t::score_type;
        using is_local_t = std::bool_constant<traits_t::is_local>;
 
    public:
        using type = std::conditional_t<traits_t::is_vectorised,
                                        deferred_crtp_base<simd_affine_gap_policy, score_t, is_local_t>,
                                        deferred_crtp_base<affine_gap_policy, score_t, is_local_t>>;
    };
 
    template <typename traits_t>
    struct select_find_optimum_policy
    {
    private:
        using score_t = typename traits_t::score_type;
 
    public:
        using type = std::conditional_t<traits_t::is_vectorised,
                                        deferred_crtp_base<simd_find_optimum_policy, score_t>,
                                        deferred_crtp_base<find_optimum_policy>>;
    };
 
    template <typename traits_t, typename... args_t>
    using select_alignment_algorithm_t = lazy_conditional_t<traits_t::is_banded,
                                                            lazy<pairwise_alignment_algorithm_banded, args_t...>,
                                                            lazy<pairwise_alignment_algorithm, args_t...>>;
 
    template <typename config_t>
    struct select_gap_recursion_policy
    {
    private:
        using traits_type = alignment_configuration_traits<config_t>;
        static constexpr bool with_trace = traits_type::requires_trace_information;
 
        using gap_recursion_policy_type = std::conditional_t<with_trace,
                                                             policy_affine_gap_with_trace_recursion<config_t>,
                                                             policy_affine_gap_recursion<config_t>>;
        using banded_gap_recursion_policy_type =
            std::conditional_t<with_trace,
                               policy_affine_gap_with_trace_recursion_banded<config_t>,
                               policy_affine_gap_recursion_banded<config_t>>;
 
    public:
        using type =
            std::conditional_t<traits_type::is_banded, banded_gap_recursion_policy_type, gap_recursion_policy_type>;
    };
 
public:
    template <align_pairwise_range_input sequences_t, typename config_t>
        requires is_type_specialisation_of_v<config_t, configuration>
    static constexpr auto configure(config_t const & cfg)
    {
        auto config_with_output = maybe_default_output(cfg);
        using config_with_output_t = decltype(config_with_output);
 
        // ----------------------------------------------------------------------------
        // Configure the type-erased alignment function.
        // ----------------------------------------------------------------------------
 
        using first_seq_t = std::tuple_element_t<0, std::ranges::range_value_t<sequences_t>>;
        using second_seq_t = std::tuple_element_t<1, std::ranges::range_value_t<sequences_t>>;
 
        using wrapped_first_t = type_reduce_t<first_seq_t &>;
        using wrapped_second_t = type_reduce_t<second_seq_t &>;
 
        // The alignment executor passes a chunk over an indexed sequence pair range to the alignment algorithm.
        using indexed_sequence_pair_range_t = typename chunked_indexed_sequence_pairs<sequences_t>::type;
        using indexed_sequence_pair_chunk_t = std::ranges::range_value_t<indexed_sequence_pair_range_t>;
 
        // Select the result type based on the sequences and the configuration.
        using alignment_result_value_t = typename align_result_selector<std::remove_reference_t<wrapped_first_t>,
                                                                        std::remove_reference_t<wrapped_second_t>,
                                                                        config_with_output_t>::type;
        using alignment_result_t = alignment_result<alignment_result_value_t>;
        using callback_on_result_t = std::function<void(alignment_result_t)>;
        // Define the function wrapper type.
        using function_wrapper_t = std::function<void(indexed_sequence_pair_chunk_t, callback_on_result_t)>;
 
        // Capture the alignment result type.
        auto config_with_result_type = config_with_output | align_cfg::detail::result_type<alignment_result_t>{};
 
        // ----------------------------------------------------------------------------
        // Test some basic preconditions
        // ----------------------------------------------------------------------------
 
        using alignment_contract_t = alignment_contract<sequences_t, config_with_output_t>;
 
        static_assert(alignment_contract_t::expects_alignment_configuration(),
                      "Alignment configuration error: "
                      "The alignment can only be configured with alignment configurations.");
 
        static_assert(alignment_contract_t::expects_tuple_like_value_type(),
                      "Alignment configuration error: "
                      "The value type of the sequence ranges must model the seqan3::tuple_like and must contain "
                      "exactly 2 elements.");
 
        static_assert(alignment_contract_t::expects_valid_scoring_scheme(),
                      "Alignment configuration error: "
                      "Either the scoring scheme was not configured or the given scoring scheme cannot be invoked with "
                      "the value types of the passed sequences.");
 
        // ----------------------------------------------------------------------------
        // Configure the algorithm
        // ----------------------------------------------------------------------------
 
        // Use default edit distance if gaps are not set.
        align_cfg::gap_cost_affine edit_gap_cost{};
        auto const & gap_cost = config_with_result_type.get_or(edit_gap_cost);
        auto const & scoring_scheme = get<align_cfg::scoring_scheme>(cfg).scheme;
 
        if constexpr (config_t::template exists<seqan3::align_cfg::method_global>())
        {
            // Only use edit distance if ...
            if constexpr (std::same_as<std::remove_cvref_t<decltype(scoring_scheme)>, hamming_scoring_scheme>)
            {
                auto method_global_cfg = get<seqan3::align_cfg::method_global>(config_with_result_type);
 
                bool const has_edit_distance_gaps = gap_cost.open_score == 0 && gap_cost.extension_score == -1;
                bool const has_no_free_end_gaps_sequence2 = !method_global_cfg.free_end_gaps_sequence2_leading
                                                         && !method_global_cfg.free_end_gaps_sequence2_trailing;
                bool const has_equal_free_end_gaps_sequence1 = method_global_cfg.free_end_gaps_sequence1_leading
                                                            == method_global_cfg.free_end_gaps_sequence1_trailing;
 
                if (has_edit_distance_gaps && has_no_free_end_gaps_sequence2 && has_equal_free_end_gaps_sequence1)
                {
                    return std::pair{configure_edit_distance<function_wrapper_t>(config_with_result_type),
                                     config_with_result_type};
                }
            }
        }
 
        // ----------------------------------------------------------------------------
        // Check if invalid configuration was used.
        // ----------------------------------------------------------------------------
 
        // Do not allow min score configuration for alignments not computing the edit distance.
        if (config_t::template exists<align_cfg::min_score>())
            throw invalid_alignment_configuration{"The align_cfg::min_score configuration is only allowed for the "
                                                  "specific edit distance computation."};
        // Configure the alignment algorithm.
        return std::pair{configure_scoring_scheme<function_wrapper_t>(config_with_result_type),
                         config_with_result_type};
    }
 
private:
    template <typename config_t>
    static constexpr auto maybe_default_output(config_t const & config) noexcept
    {
        using traits_t = alignment_configuration_traits<config_t>;
 
        if constexpr (traits_t::has_output_configuration)
            return config;
        else
            return config | align_cfg::output_score{} | align_cfg::output_begin_position{}
                 | align_cfg::output_end_position{} | align_cfg::output_alignment{} | align_cfg::output_sequence1_id{}
                 | align_cfg::output_sequence2_id{};
    }
 
    template <typename function_wrapper_t, typename config_t>
    static constexpr function_wrapper_t configure_edit_distance(config_t const & cfg)
    {
        using traits_t = alignment_configuration_traits<config_t>;
 
        // ----------------------------------------------------------------------------
        // Unsupported configurations
        // ----------------------------------------------------------------------------
 
        if constexpr (traits_t::is_banded)
            throw invalid_alignment_configuration{"Banded alignments are yet not supported."};
 
        // ----------------------------------------------------------------------------
        // Configure semi-global alignment
        // ----------------------------------------------------------------------------
 
        // Get the value for the sequence ends configuration.
        auto method_global_cfg = cfg.get_or(align_cfg::method_global{});
 
        auto configure_edit_traits = [&](auto is_semi_global)
        {
            struct edit_traits_type
            {
                using is_semi_global_type [[maybe_unused]] = std::remove_cvref_t<decltype(is_semi_global)>;
            };
 
            edit_distance_algorithm<std::remove_cvref_t<config_t>, edit_traits_type> algorithm{cfg};
            return function_wrapper_t{std::move(algorithm)};
        };
 
        // Check if it has free ends set for the first sequence trailing gaps.
        auto has_free_ends_trailing = [&](auto first) constexpr
        {
            if constexpr (!decltype(first)::value)
            {
                return configure_edit_traits(std::false_type{});
            }
            else // Resolve correct property at runtime.
            {
                if (method_global_cfg.free_end_gaps_sequence1_trailing)
                    return configure_edit_traits(std::true_type{});
                else
                    return configure_edit_traits(std::false_type{});
            }
        };
 
        // Check if it has free ends set for the first sequence leading gaps.
        if (method_global_cfg.free_end_gaps_sequence1_leading)
            return has_free_ends_trailing(std::true_type{});
        else
            return has_free_ends_trailing(std::false_type{});
    }
 
    template <typename function_wrapper_t, typename config_t>
    static constexpr function_wrapper_t configure_scoring_scheme(config_t const & cfg);
 
    template <typename function_wrapper_t, typename... policies_t, typename config_t>
    static constexpr function_wrapper_t make_algorithm(config_t const & cfg)
    {
        using traits_t = alignment_configuration_traits<config_t>;
 
        // Temporarily we will use the new and the old alignment implementation in order to
        // refactor step-by-step to the new implementation. The new implementation will be tested in
        // macrobenchmarks to show that it maintains a high performance.
 
        // Use old alignment implementation if...
        if constexpr (traits_t::is_local ||                   // it is a local alignment,
                      traits_t::is_debug ||                   // it runs in debug mode,
                      traits_t::compute_sequence_alignment || // it computes more than the begin position.
                      (traits_t::is_banded && traits_t::compute_begin_positions)
                      || // banded && more than end positions.
                      (traits_t::is_vectorised && traits_t::compute_end_positions)) // simd and more than the score.
        {
            using matrix_policy_t = typename select_matrix_policy<traits_t>::type;
            using gap_policy_t = typename select_gap_policy<traits_t>::type;
            using find_optimum_t = typename select_find_optimum_policy<traits_t>::type;
            using gap_init_policy_t = deferred_crtp_base<affine_gap_init_policy>;
 
            return alignment_algorithm<config_t,
                                       matrix_policy_t,
                                       gap_policy_t,
                                       find_optimum_t,
                                       gap_init_policy_t,
                                       policies_t...>{cfg};
        }
        else // Use new alignment algorithm implementation.
        {
            //----------------------------------------------------------------------------------------------------------
            // Configure the optimum tracker policy.
            //----------------------------------------------------------------------------------------------------------
 
            using scalar_optimum_updater_t =
                std::conditional_t<traits_t::is_banded, max_score_banded_updater, max_score_updater>;
 
            using optimum_tracker_policy_t =
                lazy_conditional_t<traits_t::is_vectorised,
                                   lazy<policy_optimum_tracker_simd, config_t, max_score_updater_simd_global>,
                                   lazy<policy_optimum_tracker, config_t, scalar_optimum_updater_t>>;
 
            //----------------------------------------------------------------------------------------------------------
            // Configure the gap scheme policy.
            //----------------------------------------------------------------------------------------------------------
 
            using gap_cost_policy_t = typename select_gap_recursion_policy<config_t>::type;
 
            //----------------------------------------------------------------------------------------------------------
            // Configure the result builder policy.
            //----------------------------------------------------------------------------------------------------------
 
            using result_builder_policy_t = policy_alignment_result_builder<config_t>;
 
            //----------------------------------------------------------------------------------------------------------
            // Configure the scoring scheme policy.
            //----------------------------------------------------------------------------------------------------------
 
            using alignment_method_t = std::
                conditional_t<traits_t::is_global, seqan3::align_cfg::method_global, seqan3::align_cfg::method_local>;
 
            using score_t = typename traits_t::score_type;
            using scoring_scheme_t = typename traits_t::scoring_scheme_type;
            constexpr bool is_aminoacid_scheme =
                is_type_specialisation_of_v<scoring_scheme_t, aminoacid_scoring_scheme>;
 
            using simple_simd_scheme_t = lazy_conditional_t<traits_t::is_vectorised,
                                                            lazy<simd_match_mismatch_scoring_scheme,
                                                                 score_t,
                                                                 typename traits_t::scoring_scheme_alphabet_type,
                                                                 alignment_method_t>,
                                                            void>;
            using matrix_simd_scheme_t = lazy_conditional_t<traits_t::is_vectorised,
                                                            lazy<simd_matrix_scoring_scheme,
                                                                 score_t,
                                                                 typename traits_t::scoring_scheme_alphabet_type,
                                                                 alignment_method_t>,
                                                            void>;
 
            using alignment_scoring_scheme_t =
                std::conditional_t<traits_t::is_vectorised,
                                   std::conditional_t<is_aminoacid_scheme, matrix_simd_scheme_t, simple_simd_scheme_t>,
                                   scoring_scheme_t>;
 
            using scoring_scheme_policy_t = policy_scoring_scheme<config_t, alignment_scoring_scheme_t>;
 
            //----------------------------------------------------------------------------------------------------------
            // Configure the alignment matrix policy.
            //----------------------------------------------------------------------------------------------------------
 
            using score_matrix_t = score_matrix_single_column<score_t>;
            using trace_matrix_t = trace_matrix_full<trace_directions>;
 
            using alignment_matrix_t =
                std::conditional_t<traits_t::requires_trace_information,
                                   combined_score_and_trace_matrix<score_matrix_t, trace_matrix_t>,
                                   score_matrix_t>;
            using alignment_matrix_policy_t = policy_alignment_matrix<traits_t, alignment_matrix_t>;
 
            //----------------------------------------------------------------------------------------------------------
            // Configure the final alignment algorithm.
            //----------------------------------------------------------------------------------------------------------
 
            using algorithm_t = select_alignment_algorithm_t<traits_t,
                                                             config_t,
                                                             gap_cost_policy_t,
                                                             optimum_tracker_policy_t,
                                                             result_builder_policy_t,
                                                             scoring_scheme_policy_t,
                                                             alignment_matrix_policy_t>;
            return algorithm_t{cfg};
        }
    }
};
 
template <typename function_wrapper_t, typename config_t>
constexpr function_wrapper_t alignment_configurator::configure_scoring_scheme(config_t const & cfg)
{
    using traits_t = alignment_configuration_traits<config_t>;
 
    using scoring_scheme_t = typename traits_t::scoring_scheme_type;
    constexpr bool is_aminoacid_scheme = is_type_specialisation_of_v<scoring_scheme_t, aminoacid_scoring_scheme>;
    using alignment_type_t = typename std::
        conditional_t<traits_t::is_global, seqan3::align_cfg::method_global, seqan3::align_cfg::method_local>;
 
    using simple_simd_scheme_t = lazy_conditional_t<traits_t::is_vectorised,
                                                    lazy<simd_match_mismatch_scoring_scheme,
                                                         typename traits_t::score_type,
                                                         typename traits_t::scoring_scheme_alphabet_type,
                                                         alignment_type_t>,
                                                    void>;
    using matrix_simd_scheme_t = lazy_conditional_t<traits_t::is_vectorised,
                                                    lazy<simd_matrix_scoring_scheme,
                                                         typename traits_t::score_type,
                                                         typename traits_t::scoring_scheme_alphabet_type,
                                                         alignment_type_t>,
                                                    void>;
 
    using alignment_scoring_scheme_t =
        std::conditional_t<traits_t::is_vectorised,
                           std::conditional_t<is_aminoacid_scheme, matrix_simd_scheme_t, simple_simd_scheme_t>,
                           scoring_scheme_t>;
 
    using scoring_scheme_policy_t = deferred_crtp_base<scoring_scheme_policy, alignment_scoring_scheme_t>;
    return make_algorithm<function_wrapper_t, scoring_scheme_policy_t>(cfg);
}
} // namespace seqan3::detail