STK_MINIMIZE_BOXCONSTRAINED performs box-constrained minimization

 CALL: U_OPT = stk_minimize_boxconstrained (ALGO, F, U_INIT, LB, UB)

   minimizes the objective function F between LB and UB, using algorithm
   ALGO with starting point U_INIT.  The best point found by the algorithm is
   returned as U_OPT.  The value of ALGO can be 'fmincon', 'octavesqp', or any
   algorithm object implementing the 'stk_minimize_boxconstrained' method.

 CALL: [U_OPT, F_OPT] = stk_minimize_boxconstrained (ALGO, F, U_INIT, LB, UB)

   also returns the best objective value F_OPT.

 See also stk_minimize_unconstrained, stk_optim_octavesqp, stk_optim_fmincon