void lagrange_solve(lmm_system_t sys);
//computes the value of the dichotomy using a initial values, init, with a specific variable or constraint
static double dichotomy(double init, double diff(double, void *), void *var_cnst, double min_error);
void lagrange_solve(lmm_system_t sys);
//computes the value of the dichotomy using a initial values, init, with a specific variable or constraint
static double dichotomy(double init, double diff(double, void *), void *var_cnst, double min_error);