more progress on drafting the worker thread model, get job batch func, etc...

inc/genetic.h

@@ -1,15 +1,19 @@
 #include <vector>
-#include <span>
 
 namespace genetic {
 
+template <class T> struct ReadonlySpan;
+template <class T> struct Span;
+template <class T> struct Stats;
+template <class T> struct Strategy;
+
+template <class T> Stats<T> run(Strategy<T>);
+
 template <class T> struct Strategy {
   int num_threads; // Number of worker threads that will be evaluating cell
                    // fitness.
-  int num_retries; // Number of times worker threads will try to grab work pool
-                   // lock before sleeping
-  int batch_size;  // Number of cells a worker thread tries to evaluate in a row
-                   // before locking the pool again.
+  int batch_size;  // Number of cells a worker thread tries to work on in a row
+                   // before accessing/locking the work queue again.
   int num_cells;   // Size of the population pool
   int num_generations; // Number of times (epochs) to run the algorithm
   bool test_all; // Sets whether or not every cell is tested every generation
@@ -21,14 +25,17 @@ template <class T> struct Strategy {
   float crossover_mutation_chance; // Chance to mutate a child cell
   int crossover_parent_num;        // Number of unique high-scoring parents in a
                                    // crossover call.
-  int crossover_children_num;      // Number of children produced in a crossover
-  bool enable_mutation;  // Cells may be mutated before fitness evaluation
+  int crossover_children_num;      // Number of children to expect the user to
+                                   // produce in the crossover function.
+  bool enable_mutation;            // Cells may be mutated
+                                   // before fitness evaluation
   float mutation_chance; // Chance to mutate cells before fitness evaluation
 
   // User defined functions
   T (*make_default_cell)();
-  void (*mutate)(T &cell);
-  void (*crossover)(const std::span<T> &parents, std::span<T> &out_children);
+  void (*mutate)(T &cell_to_modify);
+  void (*crossover)(const ReadonlySpan<T> &parents,
+                    const Span<T> &out_children);
   float (*fitness)(const T &cell);
 };
 
@@ -37,6 +44,18 @@ template <class T> struct Stats {
   std::vector<float> average_fitness;
 };
 
-template <class T> Stats<T> run(Strategy<T>);
+template <class T> struct ReadonlySpan {
+  T *_data;
+  int len;
+
+  const T &operator[](int i);
+};
+
+template <class T> struct Span {
+  T *_data;
+  int len;
+
+  T &operator[](int i);
+};
 
 } // namespace genetic