# finding no answer for large MIP using the GAMS/CPLEX

 0 My problem is that I have run a big MIP model using the CPLEX solver of GAMS and due to largeness of the problem after 3600 seconds that I have set for the model to limit the whole process, the resulting objective function is equal to zero and the message is interruption due to the resource limitation . I want to know at least the upper bound and lower bound that have been found up the 3600 second instead of the zero value of objective function. How can I? Thanks in advance for any reply, M.Tanha. asked 20 Jul '16, 10:17 mosahab 1●3 accept rate: 0%

 0 You may try barrier algorithm at root node with dual crossover and dual simplex in other nodes. May I know your problem size? answered 20 Jul '16, 13:30 Amit Sarkar 13●5 accept rate: 0%
 0 My model is as follow. I even wanted to give my model in GAMS an starting answer, as you can see in my model before the solve statement, but I am not sure that I have done it correctly. because am a begginer in advenced subjects of GAMS, Please help me so that I can handle my problem easily. Thanks in advance, scalar starttime; starttime = jnow; SETS i number of retailers /1*51/, t number of discrete time instants of the planning time horizon /1*3/ ; alias(j,i) ; PARAMETERS QQ vehicle’s capacity (=C) /3645/ , Pt perish time /20/ , x(i) x coordinate of the retailer i / 1 436 2 391 3 268 4 358 5 12 6 165 7 172 8 492 9 276 10 241 11 272 12 453 13 124 14 210 15 298 16 63 17 73 18 152 19 454 20 372 21 14 22 71 23 134 24 49 25 189 26 199 27 404 28 87 29 434 30 260 31 251 32 406 33 429 34 438 35 498 36 237 37 435 38 227 39 450 40 277 41 280 42 240 43 416 44 43 45 209 46 324 47 260 48 442 49 320 50 305 51 130 / , y(i) y coordinate of the retailer i / 1 498 2 96 3 146 4 133 5 256 6 108 7 15 8 239 9 382 10 446 11 16 12 141 13 8 14 132 15 210 16 237 17 51 18 155 19 428 20 460 21 310 22 355 23 326 24 265 25 175 26 415 27 276 28 247 29 261 30 44 31 158 32 258 33 76 34 397 35 44 36 250 37 304 38 356 39 29 40 1 41 87 42 279 43 311 44 256 45 163 46 196 47 123 48 444 49 11 50 435 51 272 / , I_0(i) starting level of the inventory at the retailer i / 1 6026 2 84 3 36 4 44 5 26 6 44 7 158 8 78 9 92 10 36 11 72 12 24 13 10 14 30 15 94 16 54 17 174 18 32 19 132 20 68 21 44 22 180 23 70 24 83 25 198 26 24 27 138 28 182 29 98 30 45 31 55 32 90 33 46 34 102 35 24 36 23 37 83 38 90 39 140 40 15 41 68 42 40 43 99 44 116 45 37 46 24 47 10 48 20 49 76 50 34 51 54 /, c(i) maximum level of the inventory at the retailer i / 1 1000000 2 168 3 54 4 66 5 39 6 66 7 237 8 156 9 138 10 72 11 144 12 48 13 20 14 45 15 141 16 81 17 261 18 64 19 198 20 136 21 66 22 270 23 140 24 166 25 297 26 48 27 207 28 273 29 147 30 90 31 110 32 180 33 69 34 153 35 48 36 46 37 166 38 135 39 210 40 30 41 136 42 60 43 198 44 174 45 74 46 48 47 20 48 30 49 152 50 68 51 81 / , r(i) quantity absorbed by the retailer i at each discrete time instant of the planning time horizon (= d(i)) / 1 2430 2 84 3 18 4 22 5 13 6 22 7 79 8 78 9 46 10 36 11 72 12 24 13 10 14 15 15 47 16 27 17 87 18 32 19 66 20 68 21 22 22 90 23 70 24 83 25 99 26 24 27 69 28 91 29 49 30 45 31 55 32 90 33 23 34 51 35 24 36 23 37 83 38 45 39 70 40 15 41 68 42 20 43 99 44 58 45 37 46 24 47 10 48 10 49 76 50 34 51 27 / , h(i) unit inventory cost at the retailer i /1 0.03 2 0.02 3 0.03 4 0.03 5 0.02 6 0.02 7 0.03 8 0.04 9 0.04 10 0.02 11 0.04 12 0.02 13 0.02 14 0.02 15 0.03 16 0.02 17 0.04 18 0.01 19 0.04 20 0.04 21 0.02 22 0.04 23 0.05 24 0.02 25 0.03 26 0.02 27 0.05 28 0.03 29 0.02 30 0.01 31 0.01 32 0.03 33 0.03 34 0.03 35 0.02 36 0.02 37 0.02 38 0.03 39 0.05 40 0.04 41 0.03 42 0.04 43 0.02 44 0.03 45 0.03 46 0.04 47 0.02 48 0.04 49 0.04 50 0.02 51 0.04 /; parameter b(i,j) ; b(i,j) = floor(sqrt(power((x(i)-x(j)),2)+power((y(i)-y(j)),2))) ; VARIABLES W(i,j,t) amount of product delivered directly Inv(i,t) Inventory in each period q(i,t) Delivery amount v(i,t) subtour elimination cost ; Binary VARIABLE x_x the routing variable ; POSITIVE VARIABLES inv ,v ,q; *POSITIVE VARIABLES w ; EQUATION OBJECTIVE const1_1 (t) const1_2 (t) const1_3 (t) const2_1 (i,t) const2_2 (i,t) const2_3 (i,t) const2_4 (i,t) const2_5 (i,t) *IRPT-OU: *const3_1 (i,t) *const3_2 (i,t) const4_1 (i,t) const4_2 (i,t) const5 (i,t) const6 (t) const7 (j,t) const8 (t) const9 (i,j,t) const10 (i,t) const11 (i,t) *const12 (i,t) *const13 (i,t) *const14 (i,j,t) *const16 (i,j,t) const17 (i,j,t) ; *OBJECTIVE.. cost =e= sum(t,h('1')*Inv('1',t)) + sum((i,t)$(ord(i) GT 1),h(i)*Inv(i,t)) + sum((i,j,t),b(i,j)*x_x(i,j,t)) + sum((i,j,t)$(ord(j) GT 1), 100*b(i,j)*w(i,j,t)); OBJECTIVE.. cost =e= sum(t,h('1')*Inv('1',t)) + sum((i,t)$(ord(i) GT 1),h(i)*Inv(i,t)) + sum((i,j,t),b(i,j)*x_x(i,j,t)) ; *const1_1 (t)$(ord(t) EQ 1) .. I_0('1') + r('1') -sum(i$(ord(i) GT 1),q(i,t))-sum(i$(ord(i) GT 1),w('1',i,t))=e=Inv('1','1'); const1_1 (t)$(ord(t) EQ 1) .. I_0('1') + r('1') -sum(i$(ord(i) GT 1),q(i,t)) =e= Inv('1','1'); *const1_2 (t)$(ord(t) GT 1) .. Inv('1',t-1)+ r('1') -sum(i$(ord(i) GT 1),q(i,t))-sum(i$(ord(i) GT 1),w('1',i,t))=e=Inv('1',t); const1_2 (t)$(ord(t) GT 1) .. Inv('1',t-1)+ r('1') -sum(i$(ord(i) GT 1),q(i,t)) =e= Inv('1',t); const1_3 (t) .. Inv('1',t) =g= 0; *const2_1 (i,t)$((ord(i) GT 1) and (ord(t) EQ 1)) .. I_0(i) +q(i,t)+sum(j,w(j,i,t))-sum(j$(ord(j) gt 1),w(i,j,t))-r(i)=e=Inv(i,t); const2_1 (i,t)$((ord(i) GT 1) and (ord(t) EQ 1)) .. I_0(i) +q(i,t)-r(i)=e=Inv(i,t); *const2_2 (i,t)$((ord(i) GT 1) and (ord(t) GT 1)) .. Inv(i,t-1)+q(i,t)+sum(j,w(j,i,t))-sum(j$(ord(j) gt 1),w(i,j,t))-r(i)=e=Inv(i,t); const2_2 (i,t)$((ord(i) GT 1) and (ord(t) GT 1)) .. Inv(i,t-1)+q(i,t)-r(i)=e=Inv(i,t); const2_3 (i,t)$(ord(i) GT 1) .. Inv(i,t) =g= 0; const2_4 (i,t)$(ord(i) GT 1) .. Inv(i,t) =l= c(i) ; const2_5 (i,t)$(ord(i) GT 1) .. Inv(i,t) =l= Pt*r(i) ; *const3_2 (i,t)$(ord(i) GT 1) .. C(i)*sum(j, x_x(i,j,t)) - Inv(i,t) =l= q(i,t); *const3_2 (i,t)$(ord(i) GT 1) .. (C(i)*sum(j$(ord(j) GT 1), x_x(i,j,t)) - Inv(i,t)) =l= q(i,t); *const3_1 (i,t)$((ord(t) EQ 1) and (ord(i) GT 1)) .. C(i)*(sum(j$((ord(j) GT 1)and(ord(i)<>ord(j))) ,x_x(i,j,t))) - Inv0(i) =l= q(i,t); *const3_2 (i,t)$((ord(t) GT 1) and (ord(i) GT 1)) .. C(i)*(sum(j$((ord(j) GT 1)and(ord(i)<>ord(j))) ,x_x(i,j,t))) - Inv(i,t-1) =l= q(i,t); *const4_2 (i,t)$(ord(i) GT 1) .. C(i) - Inv(i,t) =g= q(i,t); const4_1 (i,t)$((ord(t) EQ 1) and (ord(i) GT 1)) .. C(i) - I_0(i) =g= q(i,t); const4_2 (i,t)$((ord(t) GT 1) and (ord(i) GT 1)) .. C(i) - Inv(i,t-1) =g= q(i,t); const5 (i,t)$(ord(i) GT 1) .. C(i) * sum(j$(ord(i) <> ord(j)),x_x(i,j,t)) =g= q(i,t); const6 (t) .. sum(i$(ord(i) GT 1), q(i,t)) =l= QQ ; const7 (j,t) .. sum(i$(ord(i) <> ord(j)),x_x(i,j,t))=e= sum(i$(ord(i) <> ord(j)),x_x(j,i,t)) ; const8 (t) .. sum(i$(ord(i) GT 1),x_x(i,'1',t)) =l= 1 ; const9 (i,j,t)$((ord(i) GT 1)and(ord(j) GT 1)) .. v(i,t)-v(j,t)+ QQ*x_x(i,j,t) =l= QQ-q(j,t); const10 (i,t)$(ord(i) GT 1) .. q(i,t) =l= v(i,t); const11 (i,t)$(ord(i) GT 1) .. v(i,t) =l= QQ; *const12 (i,t)$(ord(i) GT 1) .. v(i,t) =g= 0; *const13 (i,t)$(ord(i) GT 1) .. q(i,t) =g= 0; *const14 (i,j,t)$(ord(i) EQ ord(j)) .. w(i,j,t) =e= 0; *const16 (i,j,t) .. w(i,j,t) =e= 0; const17 (i,j,t)\$(ord(i) EQ ord(j)) .. x_x(i,j,t)=e=0; MODEL transshipment5 / ALL / ; option optcr = 0.00000001; Option MIP = Cplex; *Option MIP = osicplex; Option Limrow=1000000; Option Limcol=1000000; Option SOLPRINT=on; *time limit in seconds option reslim = 36000 ; *option MipStart = 1; x_x.l('1','0','1') = 0; x_x.l('2','4','1') = 1; x_x.l('3','0','1') = 0; x_x.l('4','0','1') = 0; x_x.l('5','0','1') = 0; x_x.l('6','0','1') = 0; x_x.l('7','0','1') = 0; x_x.l('8','0','1') = 0; x_x.l('9','0','1') = 0; x_x.l('10','6','1') = 1; x_x.l('11','0','1') = 0; x_x.l('12','7','1') = 1; x_x.l('13','0','1') = 0; x_x.l('14','3','1') = 1; x_x.l('15','0','1') = 0; x_x.l('16','8','1') = 1; x_x.l('17','9','1') = 1; x_x.l('18','0','1') = 0; x_x.l('19','1','1') = 1; x_x.l('20','0','1') = 0; x_x.l('21','0','1') = 0; x_x.l('22','0','1') = 0; x_x.l('23','0','1') = 0; x_x.l('24','0','1') = 0; x_x.l('25','0','1') = 0; x_x.l('26','0','1') = 0; x_x.l('27','0','1') = 0; x_x.l('28','0','1') = 0; x_x.l('29','0','1') = 0; x_x.l('30','0','1') = 0; x_x.l('31','0','1') = 0; x_x.l('32','0','1') = 0; x_x.l('33','0','1') = 0; x_x.l('34','0','1') = 0; x_x.l('35','0','1') = 0; x_x.l('36','0','1') = 0; x_x.l('37','0','1') = 0; x_x.l('38','0','1') = 0; x_x.l('39','0','1') = 0; x_x.l('40','0','1') = 0; x_x.l('41','0','1') = 0; x_x.l('42','2','1') = 1; x_x.l('43','0','1') = 0; x_x.l('44','0','1') = 0; x_x.l('45','0','1') = 0; x_x.l('46','5','1') = 1; x_x.l('47','0','1') = 0; x_x.l('48','0','1') = 0; x_x.l('49','0','1') = 0; x_x.l('50','0','1') = 0; x_x.l('1','25','2') = 1; x_x.l('2','0','2') = 0; x_x.l('3','0','2') = 0; x_x.l('4','0','2') = 0; x_x.l('5','0','2') = 0; x_x.l('6','38','2') = 1; x_x.l('7','30','2') = 1; x_x.l('8','4','2') = 1; x_x.l('9','7','2') = 1; x_x.l('10','22','2') = 1; x_x.l('11','29','2') = 1; x_x.l('12','39','2') = 1; x_x.l('13','18','2') = 1; x_x.l('14','0','2') = 0; x_x.l('15','11','2') = 1; x_x.l('16','0','2') = 0; x_x.l('17','37','2') = 1; x_x.l('18','0','2') = 0; x_x.l('19','2','2') = 1; x_x.l('20','14','2') = 1; x_x.l('21','15','2') = 1; x_x.l('22','8','2') = 1; x_x.l('23','13','2') = 1; x_x.l('24','0','2') = 0; x_x.l('25','6','2') = 1; x_x.l('26','33','2') = 1; x_x.l('27','10','2') = 1; x_x.l('28','0','2') = 0; x_x.l('29','21','2') = 1; x_x.l('30','36','2') = 1; x_x.l('31','34','2') = 1; x_x.l('32','26','2') = 1; x_x.l('33','0','2') = 0; x_x.l('34','28','2') = 1; x_x.l('35','16','2') = 1; x_x.l('36','31','2') = 1; x_x.l('37','5','2') = 1; x_x.l('38','27','2') = 1; x_x.l('39','23','2') = 1; x_x.l('40','20','2') = 1; x_x.l('41','0','2') = 0; x_x.l('42','32','2') = 1; x_x.l('43','12','2') = 1; x_x.l('44','17','2') = 1; x_x.l('45','35','2') = 1; x_x.l('46','19','2') = 1; x_x.l('47','1','2') = 1; x_x.l('48','24','2') = 1; x_x.l('49','3','2') = 1; x_x.l('50','9','2') = 1; x_x.l('1','9','3') = 1; x_x.l('2','0','3') = 0; x_x.l('3','8','3') = 1; x_x.l('4','25','3') = 1; x_x.l('5','21','3') = 1; x_x.l('6','0','3') = 0; x_x.l('7','0','3') = 0; x_x.l('8','0','3') = 0; x_x.l('9','30','3') = 1; x_x.l('10','14','3') = 1; x_x.l('11','0','3') = 0; x_x.l('12','22','3') = 1; x_x.l('13','17','3') = 1; x_x.l('14','0','3') = 0; x_x.l('15','0','3') = 0; x_x.l('16','23','3') = 1; x_x.l('17','20','3') = 1; x_x.l('18','2','3') = 1; x_x.l('19','0','3') = 0; x_x.l('20','0','3') = 0; x_x.l('21','0','3') = 0; x_x.l('22','27','3') = 1; x_x.l('23','0','3') = 0; x_x.l('24','19','3') = 1; x_x.l('25','0','3') = 0; x_x.l('26','6','3') = 1; x_x.l('27','0','3') = 0; x_x.l('28','7','3') = 1; x_x.l('29','0','3') = 0; x_x.l('30','0','3') = 0; x_x.l('31','0','3') = 0; x_x.l('32','10','3') = 1; x_x.l('33','3','3') = 1; x_x.l('34','0','3') = 0; x_x.l('35','0','3') = 0; x_x.l('36','5','3') = 1; x_x.l('37','0','3') = 0; x_x.l('38','11','3') = 1; x_x.l('39','13','3') = 1; x_x.l('40','15','3') = 1; x_x.l('41','29','3') = 1; x_x.l('42','4','3') = 1; x_x.l('43','24','3') = 1; x_x.l('44','18','3') = 1; x_x.l('45','0','3') = 0; x_x.l('46','16','3') = 1; x_x.l('47','1','3') = 1; x_x.l('48','12','3') = 1; x_x.l('49','31','3') = 1; x_x.l('50','28','3') = 1; *option MIPStart =1; SOLVE transshipment5 using MIP minimizing cost; DISPLAY inv.l, cost.l, cost.lo, cost.up; OPTION Savepoint=1; *time record scalar elapsed; elapsed = (jnow - starttime)*24*3600; display elapsed;  answered 21 Jul '16, 06:44 mosahab 1●3 accept rate: 0%
 toggle preview community wiki

By Email:

Markdown Basics

• *italic* or _italic_
• **bold** or __bold__
• image?![alt text](/path/img.jpg "Title")
• numbered list: 1. Foo 2. Bar
• to add a line break simply add two spaces to where you would like the new line to be.
• basic HTML tags are also supported

Tags:

×191
×51
×6
×6