Function ReadTrainDatasets

catboost/libs/data/load_data.cpp:201–292

    }

    TDataProviders ReadTrainDatasets(
        TMaybe<ETaskType> taskType,
        const NCatboostOptions::TPoolLoadParams& loadOptions,
        EObjectsOrder objectsOrder,
        bool readTestData,
        TDatasetSubset learnDatasetSubset,
        TConstArrayRef<TDatasetSubset> testDatasetSubsets,
        bool forceUnitAutoPairWeights,
        TMaybe<TVector<NJson::TJsonValue>*> classLabels,
        NPar::ILocalExecutor* const executor,
        TProfileInfo* const profile
    ) {
        if (readTestData) {
            loadOptions.Validate();
        } else {
            loadOptions.ValidateLearn();
        }

        TDataProviders dataProviders;

        if (loadOptions.LearnSetPath.Inited()) {
            CATBOOST_DEBUG_LOG << "Loading features..." << Endl;
            auto start = Now();
            dataProviders.Learn = ReadDataset(
                taskType,
                loadOptions.LearnSetPath,
                loadOptions.PairsFilePath,
                loadOptions.GraphFilePath,
                loadOptions.GroupWeightsFilePath,
                loadOptions.TimestampsFilePath,
                loadOptions.BaselineFilePath,
                loadOptions.FeatureNamesPath,
                loadOptions.PoolMetaInfoPath,
                loadOptions.ColumnarPoolFormatParams,
                loadOptions.IgnoredFeatures,
                objectsOrder,
                learnDatasetSubset,
                /*loadSampleIds*/ false,
                forceUnitAutoPairWeights,
                classLabels,
                executor
            );
            CATBOOST_DEBUG_LOG << "Loading features time: " << (Now() - start).Seconds() << Endl;
            if (profile) {
                profile->AddOperation("Build learn pool");
            }
        }
        dataProviders.Test.resize(0);

        if (readTestData) {
            CATBOOST_DEBUG_LOG << "Loading test..." << Endl;
            for (int testIdx = 0; testIdx < loadOptions.TestSetPaths.ysize(); ++testIdx) {
                const NCB::TPathWithScheme& testSetPath = loadOptions.TestSetPaths[testIdx];
                const NCB::TPathWithScheme& testPairsFilePath =
                        testIdx == 0 ? loadOptions.TestPairsFilePath : NCB::TPathWithScheme();
                const NCB::TPathWithScheme& testGraphFilePath =
                        testIdx == 0 ? loadOptions.TestGraphFilePath : NCB::TPathWithScheme();
                const NCB::TPathWithScheme& testGroupWeightsFilePath =