$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,i4,x5,x6,x7,x8,objvar; Integer Variables i1,i2,i3,i4; Equations e1,e2,e3,e4,e5,e6,e7,e8,e9,e10; e1.. - 4243.28147100424/(i3*i4) + x5 =E= 0; e2.. - sqrt(0.25*sqr(i4) + sqr(0.5*i1 + 0.5*i3)) + x7 =E= 0; e3.. - 0.707213578500707*(84000 + 3000*i4)*x7/(i3*i4*(0.0833333333333333*sqr( i4) + sqr(0.5*i1 + 0.5*i3))) + x6 =E= 0; e4.. - 0.5*i4/x7 + x8 =E= 0; e5.. - sqrt(sqr(x5) + 2*x5*x6*x8 + sqr(x6)) =G= -13600; e6.. - 504000/(i2*sqr(i1)) =G= -30000; e7.. i2 - i3 =G= 0; e8.. 0.0204744897959184*sqrt(10000000000000*i1*POWER(i2,3)*i1*POWER(i2,3))*(1 - 0.0282346219657891*i1) =G= 6000; e9.. - 2.1952/(i2*POWER(i1,3)) =G= -0.25; e10.. - (1.10471*i3**2*i4 + 0.04811*i1*i2*(14 + i4)) + objvar =E= 0; * set non default bounds i1.lo = 1; i1.up = 200; i2.lo = 1; i2.up = 200; i3.lo = 1; i3.up = 20; i4.lo = 1; i4.up = 20; * set non default levels i1.l = 2; i2.l = 2; i3.l = 2; i4.l = 2; x5.l = 1; x6.l = 1; x7.l = 1; x8.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;