does this work?

CMakeLists.txt

@@ -27,7 +27,7 @@ macro(compile_options target_name)
     sanitizers(${target_name})
 endmacro()
 
-project(blt-gp VERSION 0.3.4)
+project(blt-gp VERSION 0.3.5)
 
 include(CTest)
 
@@ -46,6 +46,10 @@ find_package(Threads REQUIRED)
 
 SET(CMAKE_CXX_FLAGS_RELEASE "-O3 -g")
 
+if (NOT ${CMAKE_BUILD_TYPE})
+    set(CMAKE_BUILD_TYPE Release)
+endif ()
+
 if (NOT TARGET BLT)
     add_subdirectory(lib/blt)
 endif ()

include/blt/gp/selection.h

@@ -106,6 +106,7 @@ namespace blt::gp
 
                 const tree_t* p1;
                 const tree_t* p2;
+                size_t runs = 0;
                 // double parent_val = 0;
                 do
                 {
@@ -122,6 +123,8 @@ namespace blt::gp
                     c1.copy_fast(*p1);
                     c2->copy_fast(*p2);
 
+                    if (++runs >= config.crossover.get().get_config().max_crossover_iterations)
+                        return 0;
 #ifdef BLT_TRACK_ALLOCATIONS
                     crossover_calls.value(1);
 #endif

include/blt/gp/transformers.h

@@ -72,6 +72,8 @@ namespace blt::gp
             {
                 // number of times crossover will try to pick a valid point in the tree. this is purely based on the return type of the operators
                 u32 max_crossover_tries = 5;
+                // how many times the crossover function can fail before we will skip this operation.
+                u32 max_crossover_iterations = 10;
                 // if tree have fewer nodes than this number, they will not be considered for crossover
                 // should be at least 5 as crossover will not select the root node.
                 u32 min_tree_size = 5;
@@ -90,6 +92,11 @@ namespace blt::gp
             
             explicit crossover_t(const config_t& config): config(config)
             {}
+
+            [[nodiscard]] const config_t& get_config() const
+            {
+                return config;
+            }
             
             std::optional<crossover_point_t> get_crossover_point(gp_program& program, const tree_t& c1, const tree_t& c2) const;