14 static inline void vector_sub(const struct vector *a, const struct vector *b,
24 static inline void vector_add(const struct vector *a, const struct vector *b,
31 static inline double vector_abs(const struct vector *a)
33 return sqrt(a->x * a->x + a->y * a->y);
36 static inline void vector_scale(const struct vector *a, const double b,
43 static inline void vector_div(const struct vector *a, const double b,