* Generalized geometric programming problem * CSTR design, Dembo (1976). VARIABLES x1 x2 x3 x4 x5 x6 x7 x8 objval objective function variable; FREE VARIABLES objval; EQUATIONS f Objective function g1 g2 g3 g4 ; f .. objval =e= 0.4*x1**0.67/x7**0.67 + 0.4*x2**0.67/x8**0.67 + 10 - x1 -x2; g1 .. 0.0588*x5*x7 + 0.1*x1 =l= 1; g2 .. 0.0588*x6*x8 + 0.1*x1 + 0.1*x2 =l= 1; g3 .. 4*x3/x5 + 2/x3**0.71/x5 + 0.0588/x3**1.3*x7 =l= 1; g4 .. 4*x4/x6 + 2/x4**0.71/x6 + 0.0588*x4**1.3*x8 =l= 1; * Bounds x1.LO = 0.1; x1.UP = 10; x2.LO = 0.1; x2.UP = 10; x3.LO = 0.1; x3.UP = 10; x4.LO = 0.1; x4.UP = 10; x5.LO = 0.1; x5.UP = 10; x6.LO = 0.1; x6.UP = 10; x7.LO = 0.1; x7.UP = 10; x8.LO = 0.1; x8.UP = 10; * Starting point (global solution) * x1.L = 579.307; * x2.L = 1359.971; * x3.L = 5109.971; * x4.L = 182.018; * x5.L = 295.601; * x6.L = 217.982; * x7.L = 286.417; * x8.L = 395.601; MODEL test /ALL/; SOLVE test USING NLP MINIMIZING objval;