Simple Model

This is a version of the 'chess2' example, modified to be an Xpress Insight app. It demonstrates how to write a model so that Xpress Insight can capture or inject the model's input data, depending upon the run mode, while still allowing the model developer to run the model from outside of Xpress Insight, e.g. from the Mosel command line.

model Chess2
 uses "mmxprs"                     ! Load the Xpress-Optimizer
 uses "mminsight"                  ! Load the Insight interface

 public declarations
  ! Model inputs
  UnitTypes: set of string
  ResourceTypes: set of string

  ResourceLimits: array(ResourceTypes) of real
  ProfitPerUnit: array(UnitTypes) of real
  UnitResourceRequirements: array(UnitTypes,ResourceTypes) of real

  ! Mathematical model objects (providing model results)
  unitstobuild: array(UnitTypes) of mpvar
  ResourceLimitConstraints: array(ResourceTypes) of linctr
  MaxProfit: linctr
 end-declarations

 ! Procedure to populate model with initial input data
 procedure loaddata
  ProfitPerUnit:: (["small","large"])[5,20]
  UnitResourceRequirements:: (["small"],["wood","mc_time"]) [1,3]
  UnitResourceRequirements:: (["large"],["wood","mc_time"]) [3,2]
  ResourceLimits:: (["wood","mc_time"])[200,400]

  finalize( UnitTypes )
  finalize( ResourceTypes )
 end-procedure

 ! Procedure to build and solve optimization problem
 procedure runproblem
  ! Build whole units only
  forall(u in UnitTypes) unitstobuild(u) is_integer

  ! Define profit
  MaxProfit:= sum(u in UnitTypes) ProfitPerUnit(u)*unitstobuild(u)

  ! Don't use more than available resources
  forall(r in ResourceTypes)
   ResourceLimitConstraints(r) := ( sum(u in UnitTypes)
    UnitResourceRequirements(u,r)*unitstobuild(u) ) <= ResourceLimits(r)

  ! Solve the mixed integer problem
  insightmaximize(MaxProfit)

  ! Print the solution to the run log
  writeln("Solution:\n Objective: ", getobjval)
  forall(u in UnitTypes)
    writeln(u, ":", unitstobuild(u).sol)
 end-procedure


 ! Perform actions based on how model is being executed
 case insightgetmode of
  INSIGHT_MODE_LOAD: do
   ! Scenario is being 'loaded' through Xpress Insight
   ! Initialize input arrays and then terminate
   loaddata
  end-do

  INSIGHT_MODE_RUN: do
   ! Scenario is being 'run' through Xpress Insight
   ! Populate with Insight scenario data and then solve optimization
   insightpopulate
   runproblem
  end-do

  INSIGHT_MODE_NONE: do
  ! Model is being run outside of Xpress Insight, e.g. from the Mosel command-line tool
  ! Initialize input arrays then solve optimization
   loaddata
   runproblem
  end-do

  else
   writeln("Unknown execution mode")
 end-case

end-model