$Ontext Minimization of the weight of a speed reducer. The weight of the speed reducer is to be minimized subject to constraints on bending stress of the gear teeth, surface stress, transverse deflections of the shafts and stresses in the shaft. Datseris, P., Weight minimization of a speed reducer by heuristic and decomposition technique. Mechanism and Machine Theory, vol.17, 1982, pp. 255-262. Aguirre, A.H., Munoz Zavala, A.E., Villa Diharce, E., Botello Rionada, S., COPSO: Constrained optimization via PSO algorithm. Comunicacion Tecnica No I-07-04/22-02-2007. Center for Research in Mathematics (CIMAT), Mexico. $Offtext Variables x1, x2, x3, x4, x5, x6, x7, obj; Equations g1, g2, g3, g4, g5, g6, g7, g8, g9, g10, g11, g; * Objective function to be minimized: g.. obj =e= 0.7854*x1*POWER(x2,2)*(3.3333*POWER(x3,2) + 14.9334*x3 - 43.0934) - 1.508*x1*(POWER(x6,2)+POWER(X7,2)) + 7.4777*(POWER(x6,3)+POWER(x7,3))+ 0.7854*(x4*POWER(x6,2)+x5*POWER(x7,2)); * Constraints: g1.. 27/(x1*POWER(x2,2)*x3) - 1 =l= 0; g2.. 397.5/(x1*POWER(x2,2)*POWER(x3,2)) - 1 =l= 0; g3.. (1.93*POWER(x4,3))/(x2*x3*POWER(x6,4)) - 1 =l= 0; g4.. (1.93*POWER(x5,3))/(x2*x3*POWER(x7,4)) - 1 =l= 0; g5.. (sqrt(POWER((745*x4)/(x2*x3),2)+16900000))/(110*POWER(x6,3)) - 1 =l= 0; g6.. (sqrt(POWER((745*x5)/(x2*x3),2)+15750000))/(85*POWER(x7,3)) - 1 =l= 0; g7.. (x2*x3)/40 - 1 =l= 0; g8.. (5*x2)/x1 - 1 =l= 0; g9.. x1/(12*x2) - 1 =l= 0; g10.. (1.5*x6 + 1.9)/x4 - 1 =l= 0; g11.. (1.1*x7 + 1.9)/x5 - 1 =l= 0; * Bounds on variables x1.lo = 2.6; x1.up = 3.6; x2.lo = 0.7; x2.up = 0.8; x3.lo = 17; x3.up = 28; x4.lo = 7.3; x4.up = 8.3; x5.lo = 7.8; x5.up = 8.3; x6.lo = 2.9; x6.up = 3.9; x7.lo = 5.0; x7.up = 5.5; Model speed /all/; Solve speed minimizing obj using nlp; * End speed