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Telecommunication problems Description
Further explanation of this example:
'Applications of optimization with Xpress-MP', Chapter 12: Telecommunication problems
Source Files By clicking on a file name, a preview is opened at the bottom of this page.
Data Files
g3routing.mos (!****************************************************** Mosel Example Problems ====================== file g3routing.mos `````````````````` Routing telephone calls in a private network A private telephone network connects 5 French cities. The circuit capacity between cities is known. At any point in time, the network expects certain circuit demands. Is it feasible to satisfy all these demands? How much can be transmitted, if not all? Which is the assigned routing for the circuits? Each path between cities is represented by a list of arcs (specified as an array) between two directly connected cities. The problem is defined as a MIP, but the LP solution already provides integer values. The solution display reports unmet demand and also calculates the unused arc capacities. (c) 2008 Fair Isaac Corporation author: S. Heipcke, Apr. 2002 *******************************************************!) model "G-3 Routing telephone calls" uses "mmxprs" declarations CALLS: set of string ! Set of demands ARCS: set of string ! Set of arcs PATHS: range ! Set of paths (routes) for demands CAP: array(ARCS) of integer ! Capacity of arcs DEM: array(CALLS) of integer ! Demands between pairs of cities CINDEX: array(PATHS) of string ! Call (demand) index per path index end-declarations initializations from 'g3routing.dat' CAP DEM CINDEX end-initializations NARC:=getsize(ARCS) declarations ROUTE: array(PATHS,1..NARC) of string ! List of arcs composing the routes flow: array(PATHS) of mpvar ! Flow on paths end-declarations initializations from 'g3routing.dat' ROUTE end-initializations ! Objective: total flow on the arcs TotFlow:= sum(p in PATHS) flow(p) ! Flow within demand limits forall(d in CALLS) sum(p in PATHS | CINDEX(p) = d) flow(p) <= DEM(d) ! Arc capacities forall(a in ARCS) sum(p in PATHS, b in 1..NARC | ROUTE(p,b)=a) flow(p) <= CAP(a) forall(p in PATHS) flow(p) is_integer ! Uncomment to display the solver log ! setparam("XPRS_VERBOSE", true) ! Solve the problem maximize(TotFlow) ! Solution printing writeln("Total flow: ", getobjval) forall(d in CALLS) do writeln(d, " (demand: ", DEM(d), ", routed calls: ", getsol(sum(p in PATHS | CINDEX(p) = d) flow(p)), ")") forall(p in PATHS | CINDEX(p) = d and getsol(flow(p))>0) do write(" ", getsol(flow(p)), ":") forall(b in 1..NARC) write(" ", ROUTE(p,b)) writeln end-do end-do writeln("Unused capacity:") forall(a in ARCS) do U:=CAP(a) - getsol(sum(p in PATHS, b in 1..NARC | ROUTE(p,b)=a) flow(p)) write(if(U>0," " + a + ": " + U + "\n", "")) end-do end-model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

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