Esempio n. 1
0
        /// <summary>
        /// Samples new hyperparameters for the trainer, and sets them.
        /// Returns true if success (new hyperparameters were suggested and set). Else, returns false.
        /// </summary>
        private static bool SampleHyperparameters(MLContext context, SuggestedTrainer trainer, IEnumerable <SuggestedPipelineRunDetail> history, bool isMaximizingMetric)
        {
            var sps     = ConvertToValueGenerators(trainer.SweepParams);
            var sweeper = new SmacSweeper(context,
                                          new SmacSweeper.Arguments
            {
                SweptParameters = sps
            });

            IEnumerable <SuggestedPipelineRunDetail> historyToUse = history
                                                                    .Where(r => r.RunSucceeded && r.Pipeline.Trainer.TrainerName == trainer.TrainerName && r.Pipeline.Trainer.HyperParamSet != null && r.Pipeline.Trainer.HyperParamSet.Any());

            // get new set of hyperparameter values
            var proposedParamSet = sweeper.ProposeSweeps(1, historyToUse.Select(h => h.ToRunResult(isMaximizingMetric))).First();

            if (!proposedParamSet.Any())
            {
                return(false);
            }

            // associate proposed parameter set with trainer, so that smart hyperparameter
            // sweepers (like KDO) can map them back.
            trainer.SetHyperparamValues(proposedParamSet);

            return(true);
        }
Esempio n. 2
0
        /// <summary>
        /// Samples new hyperparameters for the trainer, and sets them.
        /// Returns true if success (new hyperparameters were suggested and set). Else, returns false.
        /// </summary>
        private static bool SampleHyperparameters(MLContext context, SuggestedTrainer trainer,
                                                  IEnumerable <SuggestedPipelineRunDetail> history, bool isMaximizingMetric, IChannel logger)
        {
            try
            {
                var sps     = ConvertToValueGenerators(trainer.SweepParams);
                var sweeper = new SmacSweeper(context,
                                              new SmacSweeper.Arguments
                {
                    SweptParameters = sps
                });

                IEnumerable <SuggestedPipelineRunDetail> historyToUse = history
                                                                        .Where(r => r.RunSucceeded && r.Pipeline.Trainer.TrainerName == trainer.TrainerName &&
                                                                               r.Pipeline.Trainer.HyperParamSet != null &&
                                                                               r.Pipeline.Trainer.HyperParamSet.Any() &&
                                                                               FloatUtils.IsFinite(r.Score));

                // get new set of hyperparameter values
                var proposedParamSet = sweeper.ProposeSweeps(1, historyToUse.Select(h => h.ToRunResult(isMaximizingMetric))).FirstOrDefault();
                if (!proposedParamSet.Any())
                {
                    return(false);
                }

                // associate proposed parameter set with trainer, so that smart hyperparameter
                // sweepers (like KDO) can map them back.
                trainer.SetHyperparamValues(proposedParamSet);

                return(true);
            }
            catch (Exception ex)
            {
                logger.Error($"SampleHyperparameters failed with exception: {ex}");
                throw;
            }
        }