Function Evaluate

go/codegen/tensorflow/codegen.go:394–432

Evaluate generates a Python program to evaluate a trained model.

(stmt *ir.EvaluateStmt, session *pb.Session)

// Evaluate generates a Python program to evaluate a trained model.
func Evaluate(stmt *ir.EvaluateStmt, session *pb.Session) (string, error) {
	modelParams, featureColumnsCode, fieldDescs, err := restoreModel(stmt.TrainStmt)
	if err != nil {
		return "", err
	}
	labelFM := stmt.TrainStmt.Label.GetFieldDesc()[0]
	validationParams := resolveParams(stmt.Attributes, "validation.")
	if len(validationParams) == 0 {
		// add default validation.metrics = "Accuracy".
		validationParams["metrics"] = "Accuracy"
	}

	filler := evaluateFiller{
		DataSource:        session.DbConnStr,
		Select:            stmt.Select,
		Estimator:         stmt.TrainStmt.Estimator,
		FieldDescs:        fieldDescs,
		FeatureColumnCode: fmt.Sprintf("{%s}", strings.Join(featureColumnsCode, ",\n")),
		Y:                 labelFM,
		ModelParams:       modelParams,
		ValidationParams:  validationParams,
		Save:              "model_save",
		ResultTable:       stmt.Into,
		HDFSNameNodeAddr:  session.HdfsNamenodeAddr,
		HiveLocation:      session.HiveLocation,
		HDFSUser:          session.HdfsUser,
		HDFSPass:          session.HdfsPass,
	}
	var program bytes.Buffer
	var tmpl = template.Must(template.New("Evaluate").Funcs(template.FuncMap{
		"intArrayToJSONString": ir.MarshalToJSONString,
		"attrToPythonValue":    ir.AttrToPythonValue,
		"DTypeToString":        ir.DTypeToString,
	}).Parse(tfEvaluateTemplateText))
	if err := tmpl.Execute(&program, filler); err != nil {
		return "", err
	}
	return program.String(), nil
}

// restoreModel reconstruct necessary python objects from TrainStmt
func restoreModel(stmt *ir.TrainStmt) (modelParams map[string]interface{}, featureColumnsCode []string, fieldDescs map[string][]*ir.FieldDesc, err error) {