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 solvemodel
  ! 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

 ! Define actions to perform in 'load' execution mode
 !@insight.execmodes.LOAD
 public procedure doload
  ! Scenario is being 'loaded' through Xpress Insight
  ! Initialize input arrays and then terminate
  loaddata
 end-procedure

 ! Define actions to perform in 'run' execution mode
 !@insight.execmodes.RUN
 public procedure dorun
  ! Scenario is being 'run' through Xpress Insight
  ! Populate with Insight scenario data and then solve optimization
  insightpopulate
  solvemodel
 end-procedure

 ! Define actions to perform when model is run standalone (without Xpress Insight)
 !@insight.execmodes.NONE
 public procedure doloadandrun
  ! Model is being run outside of Xpress Insight, e.g. from the Mosel command-line tool
  ! Initialize input arrays then solve optimization
  loaddata
  solvemodel
 end-procedure

 ! Automatically call the procedure with annotation matching the current execution mode
 insightdispatch
end-model

Insight will by default manage all public entities of supported types in the scenario, with entities storing linctr and mpvar values in the result data and all others in the input, but you can change this by adding annotations as we'll describe in section Annotations.