pathflow.h

#ifndef PATHFLOW_H
#define PATHFLOW_H

#include "fpmath.h"
#include <stddef.h>

#define MAX_LINKS 16

typedef struct {
    fp_t b;   // throughput (pkt/s)
    fp_t p;   // loss rate
    fp_t l;   // latency
    size_t q; // packets in queue
    size_t m; // packets allocated to this link
    size_t x; // redundant packets for estimated loss
    fp_t t;   // estimated transfer time for this link
} path_t;

typedef struct {
    fp_t b_ewma;
    fp_t l_ewma;
    fp_t p_ewma;
    size_t q_ewma;
    int initialized;
} path_state_t;

void pathflow_update_state(path_state_t *state, fp_t b, fp_t l, fp_t p,
                           size_t q, fp_t alpha);
typedef enum {
    PATHFLOW_SOLVER_GREEDY,
    PATHFLOW_SOLVER_DE,
    PATHFLOW_SOLVER_SA,
    PATHFLOW_SOLVER_PSO,
    PATHFLOW_SOLVER_GA,
    PATHFLOW_SOLVER_ACO,
    PATHFLOW_SOLVER_TS
} pathflow_solver_t;

#ifndef PATHFLOW_ARENA_SIZE
#define PATHFLOW_ARENA_SIZE (16 * (MAX_PACKETS + 1) * 8 + 1048576)
#endif

#include <stdint.h>

typedef struct {
    uint8_t memory[PATHFLOW_ARENA_SIZE];
    size_t offset;
} pathflow_context_t;

/* Returned when the optimizer rejects invalid input or cannot initialize the
 * selected solver. */
#define PATHFLOW_ERROR FP_FROM_INT(-1)

/* N must be in [1, MAX_LINKS], K in [1, MAX_PACKETS], Ps in [0, 100], and
 * every path must have positive throughput and non-negative latency. */
fp_t pathflow_optimize(pathflow_context_t *ctx, size_t N, size_t K,
                       path_t *path, fp_t penalty_weight, size_t Ps,
                       pathflow_solver_t solver_type);

#endif // PATHFLOW_H