$ontext Purpose: To provide a GAMS formulation for the collection of Gupta Problems Reference: Branch and bound experiments in convex nonlinear integer programming, Management Science, 1533-1546, 31, 1985. $offtext Variables i1,i2,i3,objvar; Integer Variables i1,i2,i3; Equations e1,e2,e3,e4; e1.. (-9*sqr(i1)) - 10*i1*i2 - 8*sqr(i2) - 5*sqr(i3) - 6*i3*i1 - 10*i3*i2 =G= -1000; e2.. (-6*sqr(i1)) - 8*i1*i2 - 6*sqr(i2) - 4*sqr(i3) - 2*i3*i1 - 2*i3*i2 =G= -550; e3.. (-9*sqr(i1)) - 6*sqr(i2) - 8*sqr(i3) + 2*i2*i1 + 2*i3*i2 =G= -340; e4.. - (7*sqr(i1) + 6*sqr(i2) - 15.8*i1 - 93.2*i2 + 8*sqr(i3) - 6*i3*i1 + 4*i3 *i2 - 63*i3) + objvar =E= 0; * set non default bounds i1.up = 200; i2.up = 200; i3.up = 200; * set non default levels i1.l = 1; i2.l = 1; i3.l = 1; * set non default marginals Model m / all /; m.limrow=0; m.limcol=0; $if NOT '%gams.u1%' == '' $include '%gams.u1%' Solve m using MINLP minimizing objvar;