* Cute AMPL model (translation to GAMS) * $Set N 16 Set i /i1*i%N%/; Alias(i,k); $Set M 8 Set j /j1*j%M%/; parameter a(i,k) ; a['i1', 'i1'] = 1 ; a['i1', 'i4'] = 1 ; a['i1', 'i7'] = 1 ; a['i1', 'i8'] = 1 ; a['i1','i16'] = 1 ; a['i2', 'i2'] = 1 ; a['i2', 'i3'] = 1 ; a['i2', 'i7'] = 1 ; a['i2','i10'] = 1 ; a['i3', 'i3'] = 1 ; a['i3', 'i7'] = 1 ; a['i3', 'i9'] = 1 ; a['i3','i10'] = 1 ; a['i3','i14'] = 1 ; a['i4', 'i4'] = 1 ; a['i4', 'i7'] = 1 ; a['i4','i11'] = 1 ; a['i4','i15'] = 1 ; a['i5', 'i5'] = 1 ; a['i5', 'i6'] = 1 ; a['i5','i10'] = 1 ; a['i5','i12'] = 1 ; a['i5','i16'] = 1 ; a['i6', 'i6'] = 1 ; a['i6', 'i8'] = 1 ; a['i6','i15'] = 1 ; a['i7', 'i7'] = 1 ; a['i7','i11'] = 1 ; a['i7','i13'] = 1 ; a['i8', 'i8'] = 1 ; a['i8','i10'] = 1 ; a['i8','i15'] = 1 ; a['i9', 'i9'] = 1 ; a['i9','i12'] = 1 ; a['i9','i16'] = 1 ; a['i10','i10'] = 1 ; a['i10','i14'] = 1 ; a['i11','i11'] = 1 ; a['i11','i13'] = 1 ; a['i11','i12'] = 1 ; a['i12','i14'] = 1 ; a['i13','i13'] = 1 ; a['i13','i14'] = 1 ; a['i14','i14'] = 1 ; a['i15','i15'] = 1 ; a['i16','i16'] = 1 ; parameter b(j,i) ; b['j1', 'i1'] = 0.22 ; b['j1', 'i2'] = 0.20 ; b['j1', 'i3'] = 0.19 ; b['j1', 'i4'] = 0.25 ; b['j1', 'i5'] = 0.15 ; b['j1', 'i6'] = 0.11 ; b['j1', 'i7'] = 0.12 ; b['j1', 'i8'] = 0.13 ; b['j1', 'i9'] = 1 ; b['j2', 'i1'] = -1.46 ; b['j2', 'i3'] = -1.30 ; b['j2', 'i4'] = 1.82 ; b['j2', 'i5'] = -1.15 ; b['j2', 'i7'] = 0.80 ; b['j2','i10'] = 1 ; b['j3', 'i1'] = 1.29 ; b['j3', 'i2'] = -0.89 ; b['j3', 'i5'] = -1.16 ; b['j3', 'i6'] = -0.96 ; b['j3', 'i8'] = -0.49 ; b['j3','i11'] = 1 ; b['j4', 'i1'] = -1.10 ; b['j4', 'i2'] = -1.06 ; b['j4', 'i3'] = 0.95 ; b['j4', 'i4'] = -0.54 ; b['j4', 'i6'] = -1.78 ; b['j4', 'i7'] = -0.41 ; b['j4','i12'] = 1 ; b['j5', 'i4'] = -1.43 ; b['j5', 'i5'] = 1.51 ; b['j5', 'i6'] = 0.59 ; b['j5', 'i7'] = -0.33 ; b['j5', 'i8'] = -0.43 ; b['j5','i13'] = 1 ; b['j6', 'i2'] = -1.72 ; b['j6', 'i3'] = -0.33 ; b['j6', 'i5'] = 1.62 ; b['j6', 'i6'] = 1.24 ; b['j6', 'i7'] = 0.21 ; b['j6', 'i8'] = -0.26 ; b['j6','i14'] = 1 ; b['j7', 'i1'] = 1.12 ; b['j7', 'i4'] = 0.31 ; b['j7', 'i7'] = 1.12 ; b['j7', 'i9'] = -0.36 ; b['j7','i15'] = 1 ; b['j8', 'i2'] = 0.45 ; b['j8', 'i3'] = 0.26 ; b['j8', 'i4'] = -1.10 ; b['j8', 'i5'] = 0.58 ; b['j8', 'i7'] = -1.03 ; b['j8', 'i8'] = 0.10 ; b['j8','i16'] = 1 ; parameter c(j) ; c['j1'] = 2.5 ; c['j2'] = 1.1 ; c['j3'] = -3.1 ; c['j4'] = -3.5 ; c['j5'] = 1.3 ; c['j6'] = 2.1 ; c['j7'] = 2.3 ; c['j8'] = -1.5 ; Positive Variable x(i) ; Variable obj ; Equation Eq(j),Def_obj ; Eq(j).. sum{i,(b[j,i]*x[i])} =e= c[j]; Def_obj.. obj =e=sum{i,sum{k,(a[i,k]*(sqr(x[i]) + x[i] + 1)* (sqr(x[k]) + x[k] + 1)) } } ; x.l['i1'] = 10 ; x.l['i2'] = 10 ; x.l['i3'] = 10 ; x.l['i4'] = 10 ; x.l['i5'] = 10 ; x.l['i6'] = 10 ; x.l['i7'] = 10 ; x.l['i8'] = 10 ; x.l['i9'] = 10 ; x.l['i10'] = 10 ; x.l['i11'] = 10 ; x.l['i12'] = 10 ; x.l['i13'] = 10 ; x.l['i14'] = 10 ; x.l['i15'] = 10 ; x.l['i16'] = 10 ; *"optimal solution as starting point \n"; *x.l['i1'] = 0.03984735; *x.l['i2'] = 0.7919832 ; *x.l['i3'] = 0.2028703 ; *x.l['i4'] = 0.8443579 ; *x.l['i5'] = 1.126991 ; *x.l['i6'] = 0.9347387 ; *x.l['i7'] = 1.681962 ; *x.l['i8'] = 0.1553009 ; *x.l['i9'] = 1.567870 ; *x.l['i10'] = 0 ; *x.l['i11'] = 0 ; *x.l['i12'] = 0 ; *x.l['i13'] = 0.6602041 ; *x.l['i14'] = 0 ; *x.l['i15'] = 0.6742559 ; *x.l['i16'] = 0 ; x.up(i) = 5.0 ; Model hs119 /all/; Solve hs119 using nlp minimize obj; display x.l ; obj.l = obj.l - 244.899698 ; display obj.l ;