如何在并行任务中运行Microsoft Solver Foundation

Question

我想在并行任务中运行Microsoft Solver Foundation。我尝试了下面的解决方案，它抛出了一个异常"ArgumentException:exePath must be specified when not run in a stand alone exe。"。它一个接一个地运行良好，但我需要并行运行多个任务来加快进程。

这是我的求解方法

public List<Decision> SolveDecisions(RaceWager raceWager)
{
_logger.Info("Start to solve decisions");
EnsureInputIsNotNull(raceWager);
var solver = SolverContext.GetContext(); // Exception throw here
solver.ClearModel();
var model = solver.CreateModel();
_logger.Info("Generate decisions");
var decisions = GenerateDecisions(Domain.RealNonnegative, "x", raceWager.RunWagers, raceWager.BankRoll);
model.AddDecisions(decisions.ToArray());
var decisionNames = decisions.Select(decision => decision.Name).ToList();
var sumDecisionsExpression = string.Join(" + ", decisionNames);
model.AddConstraint("budget", $"({sumDecisionsExpression}) <= {raceWager.BankRoll}");
var expectedProfitFormula = GenerateExpectedProfitSolverExpression(decisionNames, raceWager);
model.AddGoal("ExpectedProfit", GoalKind.Maximize, expectedProfitFormula);
_logger.Info("Solve decisions");
solver.Solve(
new Directive
{
TimeLimit = int.TryParse(ConfigurationManager.AppSettings["SolverTimeLimit"], out var timeLimit)
? timeLimit
: DefaultTimeLimit,
WaitLimit = int.TryParse(ConfigurationManager.AppSettings["SolverWaitLimit"], out var waitLimit)
? waitLimit
: DefaultWaitTimeLimit
});
_logger.Info("End solve decisions");
return model.Decisions.ToList();
}

当我试图将它包装成多个并行运行的任务时。

var optimizeTasks = new List<Task>();
for (var i = 0; i < 2; i++)
{
optimizeTasks.Add(Task.Run(() =>
{
_optimizeService.SolveDecisions(new RaceWager
{
BetTypeId = BetTypes.WIN,
BankRoll = 50000,
UserDefinedOverround = 1,
TotalPool = 23529.0,
RunWagers = new List<RunWager>
{
new RunWager {ModelPercentage = 0.119796574f, MarketOdds = 11.5815125f, HorsePool = 1693},
new RunWager {ModelPercentage = 0.08600821f, MarketOdds = 12.5931282f, HorsePool = 1557},
new RunWager {ModelPercentage = 0.210860476f, MarketOdds = 3.56759453f, HorsePool = 5496},
new RunWager {ModelPercentage = 0.07284866f, MarketOdds = 8.792601f, HorsePool = 2230},
new RunWager {ModelPercentage = 0.08509313f, MarketOdds = 8.622472f, HorsePool = 2274},
new RunWager {ModelPercentage = 0.0636601746f, MarketOdds = 9.83325f, HorsePool = 1994},
new RunWager {ModelPercentage = 0.06863576f, MarketOdds = 31.4727135f, HorsePool = 623},
new RunWager {ModelPercentage = 0.0714284852f, MarketOdds = 11.4529791f, HorsePool = 1712},
new RunWager {ModelPercentage = 0.0970818f, MarketOdds = 7.305328f, HorsePool = 2684},
new RunWager {ModelPercentage = 0.0276215617f, MarketOdds = 25.2024422f, HorsePool = 778},
new RunWager {ModelPercentage = 0.0531845465f, MarketOdds = 14.7646837f, HorsePool = 1328},
new RunWager {ModelPercentage = 0.0437806025f, MarketOdds = 16.903017f, HorsePool = 1160},
new RunWager {ModelPercentage = 0.06345806025f, MarketOdds = 15.234017f, HorsePool = 1260, PGIScratching = true}
}
});
}));
}
await Task.WhenAll(optimizeTasks);

在这一行代码将抛出一个异常

var solver = SolverContext.GetContext();

Exception: 'Microsoft Solver Foundation plugin solver configuration exception.'
Message: 'exePath must be specified when not running inside a stand alone exe'
StackTrace:
at System.Configuration.ConfigurationManager.OpenExeConfigurationImpl(ConfigurationFileMap fileMap, Boolean isMachine, ConfigurationUserLevel userLevel, String exePath, Boolean preLoad)
at Microsoft.SolverFoundation.Services.PluginSolverCollection.<GetPluginSolverSection>d__7.MoveNext()
at Microsoft.SolverFoundation.Services.PluginSolverCollection.Initialize()
at Microsoft.SolverFoundation.Services.PluginSolverCollection.CreatePluginSolverCollection()

如果你需要更多信息，请告诉我。提前感谢

Answer 1

好的，我可以解决我的问题了。我仍然不知道根本原因是什么，但我可以通过在构造函数中而不是在任务中创建字段来解决它。

移除此。

var solver = SolverContext.GetContext();

使用此替代

private readonly ILogger _logger;
private readonly SolverContext _solver;
public OptimizeService(ILogger logger)
{
_logger = logger;
_solver = SolverContext.GetContext();
}