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Mining and process industries Description
Further explanation of this example:
'Applications of optimization with Xpress-MP', Chapter 6: Mining and process industries (blending problems)
Source Files By clicking on a file name, a preview is opened at the bottom of this page.
Data Files
a1alloy.mos (!****************************************************** Mosel Example Problems ====================== file a1alloy.mos ```````````````` Production of alloys An order of steel must be met with a range of carbon, copper, and manganese grades. Given the raw materials in stock, the objective is to determine the composition of the steel that minimizes the production cost. Simple linear programming blending problem formulation includes data with numerical indices and introduction of if-then statement for solution printout. (c) 2008 Fair Isaac Corporation author: S. Heipcke, Feb. 2002 *******************************************************!) model "A-1 Production of Alloys" uses "mmxprs" declarations COMP = 1..3 ! Components (chemical elements) RAW = 1..7 ! Raw materials (alloys) P: array(RAW,COMP) of real ! Composition of raw materials (in percent) PMIN,PMAX: array(COMP) of real ! Min. & max. requirements for components AVAIL: array(RAW) of real ! Raw material availabilities COST: array(RAW) of real ! Raw material costs per tonne DEM: real ! Amount of steel to produce use: array(RAW) of mpvar ! Quantity of raw mat. used produce: mpvar ! Quantity of steel produced end-declarations initializations from 'a1alloy.dat' P PMIN PMAX AVAIL COST DEM end-initializations ! Objective function Cost:= sum(r in RAW) COST(r)*use(r) ! Quantity of steel produced = sum of raw material used produce = sum(r in RAW) use(r) ! Guarantee min. and max. percentages of every chemical element forall(c in COMP) do sum(r in RAW) P(r,c)*use(r) >= PMIN(c)*produce sum(r in RAW) P(r,c)*use(r) <= PMAX(c)*produce end-do ! Use raw materials within their limit of availability forall(r in RAW) use(r) <= AVAIL(r) ! Satisfy the demand produce >= DEM ! Solve the problem minimize(Cost) ! Solution printing declarations NAMES: array(RAW) of string end-declarations initializations from 'a1alloy.dat' ! Get the names of the alloys NAMES end-initializations writeln("Total cost: ", getobjval) writeln("Amount of steel produced: ", getsol(produce)) writeln("Alloys used:") forall(r in RAW) if(getsol(use(r))>0) then write(NAMES(r), ": ", getsol(use(r))," ") end-if write("\nPercentages (C, Cu, Mn): ") forall(c in COMP) write( getsol(sum(r in RAW) P(r,c)*use(r))/getsol(produce), "% ") writeln end-model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

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