Rob
I am getting infeasibility. I am trying to figure it out but no luck yet.
var Is_LSP {LSP} binary;
var IsLSPDC {LSP,DC} binary;
/* declare Constants*/
NUM BigM;
num LAX_Min;
num LAX_Max;
num SAV_Min; num SAV_Max;
READ DATA STDOPT.PN3158_ALT6_SPECIFICS(where=(RateMatchDest = "LAX")) INTO LAX_Min=FEU;
READ DATA STDOPT.PN3158_ALT6_SPECIFICS(where=(RateMatchDest = "LAX")) INTO LAX_Max=FEU;
READ DATA STDOPT.PN3158_ALT6_SPECIFICS(where=(RateMatchDest = "SAV")) INTO SAV_Min=FEU;
READ DATA STDOPT.PN3158_ALT6_SPECIFICS(where=(RateMatchDest = "SAV")) INTO SAV_Max=FEU;
LAX_Min=0.1*LAX_Min;LAX_Max=0.3*LAX_Max;
SAV_Min=0.1*SAV_Min;SAV_Max=0.3*SAV_Max;
Here are my general constraints:
/* GENERAL CONSTRAINTS */
con Min_Qty_at_LSP_is_Respected {c in LSP}:
sum{p in Ports,t in Transit,d in DC} ContainersfromPortstoLSPtoDC [p,t,c,d]>=Min_Qty_LSP*Is_LSP[c];
con ModelOutput_Same_As_ModelInput {p in Ports, d in DC}:
sum {t in Transit,c in LSP} ContainersfromPortstoLSPtoDC[p,t,c, d] = Containers [p,d];
con CheckLSP {c in LSP}: ContainersatLSP[c] <= BigM*Is_LSP[c];
Here are my specifc constraints:
/*Constraint for retricting DC-LSP: given DC can by served by "x" number of LSPs*/
/*LAX - I am trying to Restrict LAX to exactly 5 carriers. This works fine */
num LAX_LSPs=5;
con LAX_LSP: sum{c in LSP} IsLSPDC[c,'LAX'] = LAX_LSPs;
con LAX_LSP_Link1{p in Ports, t in Transit,c in lsp, d in {'LAX'}}:
ContainersfromPortstoLSPtoDC[p,t,c,'LAX'] <= BigM * IsLSPDC[C,'LAX'];
con LAX_LSPLink2{c in LSP, d in DC}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,d] >= IsLSPDC[c,d];
/*SAV- same like LAX but the number is 4. This works fine as well. */
num SAV_LSPs=4;
con SAV_LSP: sum{c in LSP} IsLSPDC[c,'SAV'] = SAV_LSPs;
con SAV_LSP_Link1{p in Ports, t in Transit,c in lsp, d in {'SAV'}}:
ContainersfromPortstoLSPtoDC[p,t,c,'SAV'] <= BigM * IsLSPDC[C,'SAV'];
con SAV_LSPLink2{c in LSP, d in DC}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,d] >= IsLSPDC[c,d];
/* After having forced a x number of LSPs for a given carrier, we want to make sure
the lowest and the highest a carrier can get is a set number */
/*LAX*/
con LAX_MIN_LSP {c in LSP, d in {'LAX'}}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,'LAX'] >=LAX_Min*IsLSPDC[c,'LAX'];
con LAX_MAX_LSP {c in LSP, d in {'LAX'}}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,'LAX'] <=LAX_Max*IsLSPDC[c,'LAX'];
/*SAV*/
con SAV_MIN_LSP {c in LSP, d in {'SAV'}}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,'SAV'] >=SAV_Min*IsLSPDC[c,'SAV'];
con SAV_MAX_LSP {c in LSP, d in {'SAV'}}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,'SAV'] <=SAV_Max*IsLSPDC[c,'SAV'];
Till Now, it worked correctly. When i added these constraint below, I get infeasibility.
/*For any Destination that is not LAX and SAV, #of Carriers per DC is 1 - I tried numbers from 1-7 but all came infeasible. So something is not right with the way I have written my constraint that it causes infeasibility. The 14,000 number that you see is Total FEU minus LAX and SAV combined.*/
num DC_LSP_Directs=1;
con DC_LSP_Direct:
sum{c in LSP, d in DC: d not in {'SAV','LAX'}} IsLSPDC[c,d] = DC_LSP_Directs;
con DC_LSP_Direct_Link1{p in Ports, t in Transit, c in lsp, d in DC: d not in {'SAV','LAX'}}:
ContainersfromPortstoLSPtoDC[p,t,c,d] <= 14000 * IsLSPDC[c,d];
con DC_LSPL_Directink2{c in LSP, d in DC: d not in {'SAV','LAX'}}:
sum {p in Ports, t in Transit} ContainersfromPortstoLSPtoDC[p,t,c,d] >= IsLSPDC[c,d];
