maxBusyHours constraint

CMakeLists.txt

@@ -164,6 +164,7 @@ add_library(jres_solver_lib
   src/analysis/capacity_analyzer.cpp
   src/constraints/balancing.cpp
   src/constraints/minimum_rest.cpp
+  src/constraints/max_busy_time.cpp
 )
 set_target_properties(jres_solver_lib PROPERTIES OUTPUT_NAME "jres_solver")
 

README.md

@@ -34,6 +34,7 @@ The C-API uses the following structs to pass data to and from the solver.
 | :--- | :--- | :--- |
 | `consecutiveStints` | `int` | Hard constraint: Required number of consecutive stints a driver must perform (block size). |
 | `minimumRestHours` | `int` | Hard constraint: Minimum contiguous rest time required once per race. |
+| `maxBusyHours` | `int` | Hard constraint: Maximum total time (driving + spotting) a member can work before a required rest. |
 | `firstStintDriver` | `const char*` | Hard constraint: The name of the team member who must drive the first stint. |
 | `teamMembers` | `JresTeamMember*` | A pointer to an array of team members. |
 | `teamMembers_len` | `int` | The number of team members. |
@@ -182,6 +183,7 @@ The `raceDataJson` string passed to `jres_input_from_json` must strictly follow
 | :--- | :--- | :--- | :--- |
 | `consecutiveStints` | Integer | No (Default `1`) | Hard constraint: Required number of consecutive stints a driver must perform (block size). |
 | `minimumRestHours` | Integer | No (Default `0`) | Hard constraint: Minimum contiguous rest time required once per race. |
+| `maxBusyHours` | Integer | No (Default `8`) | Hard constraint: Maximum total time (driving + spotting) a member can work before a required rest. |
 | `firstStintDriver` | String | No | Hard constraint: The name of the team member who must drive the first stint. |
 | `teamMembers` | Array | Yes | List of drivers and spotters (see below). |
 | `availability` | Object | Yes | Map of availability constraints (see below). |

TOOLS.md

@@ -58,6 +58,10 @@ jres_solver.exe [options]
 | `-d` | `--diagnose`         | Run in **Diagnostic Mode** to explain why a schedule is infeasible.                           | `false` |
 | `-h` | `--help`             | Print usage instructions.                                                                     |         |
 
+> [!TIP]
+> **Constraint Configuration:**
+> While some options are available as CLI flags, core schedule constraints such as `maxBusyHours`, `minimumRestHours`, and `consecutiveStints` are defined strictly within the **Input JSON** file. See [README](./README.md#input-json-specification) for details.
+
 ### Spotter Modes
 
 #### Integrated Mode (`JRES_SPOTTER_MODE_INTEGRATED`)

include/jres_solver/jres_solver.hpp

@@ -122,6 +122,8 @@ struct JresSolverInput {
     int consecutiveStints;
     /** @brief Minimum rest time in hours required after a shift. */
     int minimumRestHours;
+    /** @brief Maximum busy time in hours (driving or spotting) before a rest is required. */
+    int maxBusyHours;
     /** @brief The name of the team member who must drive the first stint. */
     const char* firstStintDriver;
     /** @brief A pointer to an array of team members. */

src/constraints/max_busy_time.cpp

@@ -0,0 +1,97 @@
+#include "max_busy_time.hpp"
+#include "Highs.h"
+#include <chrono>
+#include <map>
+
+namespace jres::constraints {
+
+void apply_max_busy_time_constraints(
+    Highs &highs,
+    const jres::internal::SolverInput& input,
+    const std::vector<jres::internal::TeamMember> &participants,
+    const std::map<std::pair<std::string, int>, int>& driverVars,
+    const std::map<std::pair<std::string, int>, int>& spotterVars,
+    bool enforceCombined,
+    std::map<int, jres::internal::SlackInfo>& slackInfo,
+    const std::vector<jres::internal::ScheduleEntry>* fixedSchedule
+)
+{
+    using namespace jres::internal;
+
+    if (input.maxBusyHours <= 0) return;
+
+    // Calculate durations
+    std::vector<double> stintDurations;
+    stintDurations.reserve(input.stints.size());
+    for (const auto& stint : input.stints) {
+        auto s = TimeHelpers::stringToTimePoint(stint.startTime);
+        auto e = TimeHelpers::stringToTimePoint(stint.endTime);
+        long long ms = std::chrono::duration_cast<std::chrono::milliseconds>(e - s).count();
+        stintDurations.push_back(static_cast<double>(ms) / 3600000.0);
+    }
+
+    for (const auto &p : participants)
+    {
+        for (size_t s = 0; s < input.stints.size(); ++s) {
+            double currentDuration = 0.0;
+            for (size_t e = s; e < input.stints.size(); ++e) {
+                currentDuration += stintDurations[e];
+
+                if (currentDuration > input.maxBusyHours) {
+                    // Violation if assigned to ALL stints in [s, e]
+                    // Constraint: Sum(coeff * x[k]) <= (e - s)
+
+                    std::map<int, double> coefficients;
+                    int fixedAssignments = 0;
+
+                    for (size_t k = s; k <= e; ++k) {
+                        // Driver
+                        if (fixedSchedule) {
+                            // Sequential Mode: Check fixed schedule
+                            if (k < fixedSchedule->size() && (*fixedSchedule)[k].driver == p.name) {
+                                fixedAssignments++;
+                            }
+                        } else {
+                            // Integrated Mode: Add driver var to constraint
+                            if (driverVars.count({p.name, (int)k})) {
+                                coefficients[driverVars.at({p.name, (int)k})] += 1.0;
+                            }
+                        }
+
+                        // Spotter
+                        if (spotterVars.count({p.name, (int)k})) {
+                             if (fixedSchedule || enforceCombined) {
+                                 coefficients[spotterVars.at({p.name, (int)k})] += 1.0;
+                             }
+                        }
+                    }
+
+                    std::vector<int> idx;
+                    std::vector<double> val;
+                    idx.reserve(coefficients.size());
+                    val.reserve(coefficients.size());
+
+                    for(const auto& [col, coeff] : coefficients) {
+                        idx.push_back(col);
+                        val.push_back(coeff);
+                    }
+
+                    double maxAssignments = static_cast<double>(e - s);
+
+                    if (fixedSchedule) {
+                        // Adjust RHS
+                        maxAssignments -= fixedAssignments;
+                    }
+
+                    if (!idx.empty() || maxAssignments < 0) {
+                        highs.addRow(-kHighsInf, maxAssignments, (int)idx.size(), idx.data(), val.data());
+                    }
+
+                    break; 
+                }
+            }
+        }
+    }
+}
+
+} // namespace jres::constraints

src/constraints/max_busy_time.hpp

@@ -0,0 +1,21 @@
+#pragma once
+#include "../jres_internal_types.hpp"
+#include <map>
+#include <vector>
+
+class Highs;
+
+namespace jres::constraints {
+
+void apply_max_busy_time_constraints(
+    Highs &highs,
+    const jres::internal::SolverInput& input,
+    const std::vector<jres::internal::TeamMember> &participants,
+    const std::map<std::pair<std::string, int>, int>& driverVars,
+    const std::map<std::pair<std::string, int>, int>& spotterVars,
+    bool enforceCombined,
+    std::map<int, jres::internal::SlackInfo>& slackInfo,
+    const std::vector<jres::internal::ScheduleEntry>* fixedSchedule = nullptr
+);
+
+}

src/jres_internal_types.cpp

@@ -67,6 +67,7 @@ SolverInput from_c_input(const JresSolverInput* c_input) {
 
     input.consecutiveStints = c_input->consecutiveStints;
     input.minimumRestHours = c_input->minimumRestHours;
+    input.maxBusyHours = c_input->maxBusyHours;
     if (c_input->firstStintDriver) {
         input.firstStintDriver = c_input->firstStintDriver;
     }

src/jres_internal_types.hpp

@@ -47,6 +47,7 @@ struct SolverInput
 {
     int consecutiveStints = 1;
     int minimumRestHours = 0;
+    int maxBusyHours = 8;
     std::string firstStintDriver;
     std::vector<TeamMember> teamMembers;
     std::map<std::string, std::map<std::string, Availability>> availability;

src/jres_json_converter.cpp

@@ -76,6 +76,7 @@ JRES_SOLVER_API JresSolverInput* jres_input_from_json(const char* jsonData) {
         // Global Constraints
         input->consecutiveStints = j.value("consecutiveStints", 1);
         input->minimumRestHours = j.value("minimumRestHours", 0);
+        input->maxBusyHours = j.value("maxBusyHours", 8);
 
         if (j.contains("firstStintDriver") && !j["firstStintDriver"].is_null()) {
             input->firstStintDriver = allocate_and_copy(j["firstStintDriver"]);

src/jres_standard_solver.cpp

@@ -7,6 +7,7 @@
 #include "analysis/capacity_analyzer.hpp"
 #include "constraints/balancing.hpp"
 #include "constraints/minimum_rest.hpp"
+#include "constraints/max_busy_time.hpp"
 #include <algorithm>
 #include <cmath>
 #include <chrono>
@@ -322,6 +323,7 @@ jres::internal::SolverOutput JresStandardSolver::solve()
     // Apply Rest Constraints
     bool enforceCombinedRest = (m_options.spotterMode == JRES_SPOTTER_MODE_INTEGRATED);
     jres::constraints::apply_minimum_rest_constraints(*m_highs, m_input, m_input.teamMembers, m_driverWorkVars, m_spotterWorkVars, enforceCombinedRest, m_slackInfo);
+    jres::constraints::apply_max_busy_time_constraints(*m_highs, m_input, m_input.teamMembers, m_driverWorkVars, m_spotterWorkVars, enforceCombinedRest, m_slackInfo);
 
 
     // --- Solve Main Model (Drivers + Spotters if Integrated) ---
@@ -462,6 +464,9 @@ jres::internal::SolverOutput JresStandardSolver::solve()
                 }
             }
 
+            // Apply Max Busy Constraints (taking fixed drivers into account)
+            jres::constraints::apply_max_busy_time_constraints(spotterSolver, m_input, m_input.teamMembers, m_driverWorkVars, m_spotterWorkVars, true, m_slackInfo, &output.schedule);
+
             // Incentivize Spotting Adjacent to Driving (Proximity & Role Coupling)
             // Calculate Rewards per Block Var
             std::map<int, double> spotterRewards;

test/CMakeLists.txt

@@ -36,6 +36,9 @@ add_executable(solver_tests
   test_rotation_beat.cpp
   test_spotter_balancing.cpp
   test_first_stint.cpp
+  test_max_busy.cpp
+  test_max_busy_mixed_roles.cpp
+  test_max_busy_defaults.cpp
 )
 
 add_dependencies(solver_tests jres_solver_lib)