Merge pull request #1375 from reyoung/feature/EvaluatorValue

Feature/evaluator value

paddle/gserver/evaluators/CTCErrorEvaluator.cpp

@@ -20,7 +20,7 @@ namespace paddle {
 /**
  * calculate sequence-to-sequence edit distance
  */
-class CTCErrorEvaluator : public Evaluator {
+class CTCErrorEvaluator : public NotGetableEvaluator {
 private:
   MatrixPtr outActivations_;
   int numTimes_, numClasses_, numSequences_, blank_;

paddle/gserver/evaluators/Evaluator.cpp

@@ -13,9 +13,9 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #include "paddle/gserver/evaluators/Evaluator.h"
-#include "paddle/utils/Stat.h"
-
 #include "paddle/gserver/gradientmachines/NeuralNetwork.h"
+#include "paddle/utils/Stat.h"
+#include "paddle/utils/StringUtil.h"
 
 DECLARE_int32(trainer_id);
 
@@ -122,6 +122,10 @@ public:
   virtual void distributeEval(ParameterClient2* client) {
     mergeResultsOfAllClients(client);
   }
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const { return "classification_error"; }
 };
 
 /**
@@ -160,6 +164,10 @@ public:
   virtual void distributeEval(ParameterClient2* client) {
     mergeResultsOfAllClients(client);
   }
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const { return "seq_classification_error"; }
 };
 REGISTER_EVALUATOR(seq_classification_error,
                    SequenceClassificationErrorEvaluator);
@@ -250,6 +258,10 @@ public:
 private:
   IVectorPtr cpuLabel_;
   MatrixPtr cpuWeight_;
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const { return "sum"; }
 };
 /**
  * @brief column sum Evaluator
@@ -357,10 +369,18 @@ public:
   }
 
 private:
-  ColumnSumEvaluator() {}
   int32_t colIdx_;
   size_t colNum_;
   MatrixPtr sum_; /* cpu matrix */
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const {
+    if (colIdx_ == -1)
+      return "last-column-sum";
+    else
+      return "column-sum";
+  }
 };
 
 void AucEvaluator::start() {
@@ -469,6 +489,16 @@ double AucEvaluator::calcAuc() const {
   }
 }
 
+real AucEvaluator::getValueImpl() const { return calcAuc(); }
+
+std::string AucEvaluator::getTypeImpl() const {
+  if (colIdx_ == -1) {
+    return "last-column-auc";
+  } else {
+    return "auc";
+  }
+}
+
 // class RankAucEvaluator
 REGISTER_EVALUATOR(rankauc, RankAucEvaluator);
 
@@ -548,12 +578,15 @@ double RankAucEvaluator::calcRankAuc(real* outputData,
                                         : aucTmp / (clickSum * noClickSum);
 }
 
+std::string RankAucEvaluator::getTypeImpl() const { return "rankauc"; }
+
 // class PrecisionRecallEvaluator
 REGISTER_EVALUATOR(precision_recall, PrecisionRecallEvaluator);
 
 void PrecisionRecallEvaluator::start() {
   Evaluator::start();
   statsInfo_.clear();
+  values_.clear();
 }
 
 real PrecisionRecallEvaluator::evalImp(std::vector<Argument>& arguments) {
@@ -614,52 +647,23 @@ real PrecisionRecallEvaluator::evalImp(std::vector<Argument>& arguments) {
 }
 
 void PrecisionRecallEvaluator::printStats(std::ostream& os) const {
-  int label = config_.positive_label();
-  if (label != -1) {
-    CHECK(label >= 0 && label < (int)statsInfo_.size())
-        << "positive_label [" << label << "] should be in range [0, "
-        << statsInfo_.size() << ")";
-    double precision =
-        calcPrecision(statsInfo_[label].TP, statsInfo_[label].FP);
-    double recall = calcRecall(statsInfo_[label].TP, statsInfo_[label].FN);
-    os << "positive_label=" << label << " precision=" << precision
-       << " recall=" << recall
-       << " F1-score=" << calcF1Score(precision, recall);
-    return;
-  }
-
-  // micro average method: precision = (TP1+TP2)/(TP1+FP1+TP2+FP2)
-  // macro average method: precision = (precision1+precision2)/2
-  double microTotalTP = 0;
-  double microTotalFP = 0;
-  double microTotalFN = 0;
-  double macroAvgPrecision = 0;
-  double macroAvgRecall = 0;
-  size_t numLabels = statsInfo_.size();
-  for (size_t i = 0; i < numLabels; ++i) {
-    microTotalTP += statsInfo_[i].TP;
-    microTotalFP += statsInfo_[i].FP;
-    microTotalFN += statsInfo_[i].FN;
-    macroAvgPrecision += calcPrecision(statsInfo_[i].TP, statsInfo_[i].FP);
-    macroAvgRecall += calcRecall(statsInfo_[i].TP, statsInfo_[i].FN);
-  }
-  macroAvgPrecision /= numLabels;
-  macroAvgRecall /= numLabels;
-  double macroAvgF1Score = calcF1Score(macroAvgPrecision, macroAvgRecall);
-  os << "macro-average-precision=" << macroAvgPrecision
-     << " macro-average-recall=" << macroAvgRecall
-     << " macro-average-F1-score=" << macroAvgF1Score;
-
-  double microAvgPrecision = calcPrecision(microTotalTP, microTotalFP);
-  double microAvgRecall = calcPrecision(microTotalTP, microTotalFN);
-  double microAvgF1Score = calcF1Score(microAvgPrecision, microAvgRecall);
-  if (!isMultiBinaryLabel_) {
-    // precision and recall are equal in this case
-    os << " micro-average-precision=" << microAvgPrecision;
-  } else {
-    os << " micro-average-precision=" << microAvgPrecision
-       << " micro-average-recall=" << microAvgRecall
-       << " micro-average-F1-score=" << microAvgF1Score;
+  PrintStatsInfo info;
+  bool containMacroMicroInfo = getStatsInfo(&info);
+  os << "positive_label=" << config_.positive_label()
+     << " precision=" << info.precision << " recall=" << info.recall
+     << " F1-score=" << info.f1;
+  if (containMacroMicroInfo) {
+    os << "macro-average-precision=" << info.macroAvgPrecision
+       << " macro-average-recall=" << info.macroAvgRecall
+       << " macro-average-F1-score=" << info.macroAvgF1Score;
+    if (!isMultiBinaryLabel_) {
+      // precision and recall are equal in this case
+      os << " micro-average-precision=" << info.microAvgPrecision;
+    } else {
+      os << " micro-average-precision=" << info.microAvgPrecision
+         << " micro-average-recall=" << info.microAvgRecall
+         << " micro-average-F1-score=" << info.microAvgF1Score;
+    }
   }
 }
 
@@ -741,6 +745,60 @@ void PrecisionRecallEvaluator::calcStatsInfoMulti(const MatrixPtr& output,
   }
 }
 
+void PrecisionRecallEvaluator::storeLocalValues() const {
+  if (this->values_.size() == 0) {
+    PrintStatsInfo info;
+    bool containMacroMicroInfo = getStatsInfo(&info);
+    values_["precision"] = info.precision;
+    values_["recal"] = info.recall;
+    values_["F1-score"] = info.f1;
+    if (containMacroMicroInfo) {
+      values_["macro-average-precision"] = info.macroAvgPrecision;
+      values_["macro-average-recall"] = info.macroAvgRecall;
+      values_["macro-average-F1-score"] = info.macroAvgF1Score;
+      if (!isMultiBinaryLabel_) {
+        // precision and recall are equal in this case
+        values_["micro-average-precision"] = info.microAvgPrecision;
+      } else {
+        values_["micro-average-precision"] = info.microAvgPrecision;
+        values_["micro-average-recall"] = info.microAvgRecall;
+        values_["micro-average-F1-score"] = info.microAvgF1Score;
+      }
+    }
+  }
+}
+
+void PrecisionRecallEvaluator::getNames(std::vector<std::string>* names) {
+  this->storeLocalValues();
+  names->reserve(this->values_.size());
+  for (auto it = this->values_.begin(); it != this->values_.end(); ++it) {
+    names->push_back(this->config_.name() + "." + it->first);
+  }
+}
+
+real PrecisionRecallEvaluator::getValue(const std::string& name,
+                                        Error* err) const {
+  this->storeLocalValues();
+  std::vector<std::string> buffers;
+  paddle::str::split(name, '.', &buffers);
+  auto it = this->values_.find(buffers[buffers.size() - 1]);
+  if (it == this->values_.end()) {  // not found
+    *err = Error("No such key %s", name.c_str());
+    return .0f;
+  }
+
+  return it->second;
+}
+
+std::string PrecisionRecallEvaluator::getType(const std::string& name,
+                                              Error* err) const {
+  this->getValue(name, err);
+  if (!err->isOK()) {
+    return "";
+  }
+  return "precision_recall";
+}
+
 void PrecisionRecallEvaluator::distributeEval(ParameterClient2* client) {
   size_t size = 4 * statsInfo_.size();
   double* buf = new double[size];
@@ -760,6 +818,47 @@ void PrecisionRecallEvaluator::distributeEval(ParameterClient2* client) {
   delete[] buf;
 }
 
+bool PrecisionRecallEvaluator::getStatsInfo(
+    PrecisionRecallEvaluator::PrintStatsInfo* info) const {
+  int label = config_.positive_label();
+  if (label != -1) {
+    CHECK(label >= 0 && label < (int)statsInfo_.size())
+        << "positive_label [" << label << "] should be in range [0, "
+        << statsInfo_.size() << ")";
+    info->precision = calcPrecision(statsInfo_[label].TP, statsInfo_[label].FP);
+    info->recall = calcRecall(statsInfo_[label].TP, statsInfo_[label].FN);
+    info->f1 = calcF1Score(info->precision, info->recall);
+    return false;
+  }
+
+  // micro average method: precision = (TP1+TP2)/(TP1+FP1+TP2+FP2)
+  // macro average method: precision = (precision1+precision2)/2
+  double microTotalTP = 0;
+  double microTotalFP = 0;
+  double microTotalFN = 0;
+  info->macroAvgPrecision = 0;
+  info->macroAvgRecall = 0;
+  size_t numLabels = statsInfo_.size();
+  for (size_t i = 0; i < numLabels; ++i) {
+    microTotalTP += statsInfo_[i].TP;
+    microTotalFP += statsInfo_[i].FP;
+    microTotalFN += statsInfo_[i].FN;
+    info->macroAvgPrecision +=
+        calcPrecision(statsInfo_[i].TP, statsInfo_[i].FP);
+    info->macroAvgRecall += calcRecall(statsInfo_[i].TP, statsInfo_[i].FN);
+  }
+  info->macroAvgPrecision /= numLabels;
+  info->macroAvgRecall /= numLabels;
+  info->macroAvgF1Score =
+      calcF1Score(info->macroAvgPrecision, info->macroAvgRecall);
+
+  info->microAvgPrecision = calcPrecision(microTotalTP, microTotalFP);
+  info->microAvgRecall = calcPrecision(microTotalTP, microTotalFN);
+  info->microAvgF1Score =
+      calcF1Score(info->microAvgPrecision, info->microAvgRecall);
+  return true;
+}
+
 REGISTER_EVALUATOR(pnpair, PnpairEvaluator);
 void PnpairEvaluator::start() {
   Evaluator::start();
@@ -884,6 +983,8 @@ void PnpairEvaluator::calc(std::vector<PredictionResult>& predictArray) {
             << " calc total special pair: " << special;
 }
 
+std::string PnpairEvaluator::getTypeImpl() const { return "pnpair"; }
+
 ClassRegistrar<Evaluator> Evaluator::registrar_;
 Evaluator* Evaluator::create(const EvaluatorConfig& config) {
   Evaluator* evaluator = registrar_.createByType(config.type());
@@ -905,7 +1006,7 @@ static InitFunction __reg_type_auc_sum__([]() {
  *
  * The config file api is value_printer_evaluator.
  */
-class ValuePrinter : public Evaluator {
+class ValuePrinter : public NotGetableEvaluator {
 public:
   virtual void eval(const NeuralNetwork& nn) {
     for (const std::string& name : config_.input_layers()) {
@@ -919,12 +1020,13 @@ public:
   virtual real evalImp(std::vector<Argument>& arguments) { return 0; }
 };
 REGISTER_EVALUATOR(value_printer, ValuePrinter);
+
 /**
  * @brief print gradient of each layer.
  *
  * The config file api is gradient_printer_evaluator.
  */
-class GradientPrinter : public Evaluator {
+class GradientPrinter : public NotGetableEvaluator {
 public:
   virtual void eval(const NeuralNetwork& nn) {
     for (const std::string& name : config_.input_layers()) {
@@ -947,7 +1049,7 @@ REGISTER_EVALUATOR(gradient_printer, GradientPrinter);
  *
  * The config file api is maxid_printer_evaluator.
  */
-class MaxIdPrinter : public Evaluator {
+class MaxIdPrinter : public NotGetableEvaluator {
 private:
   IVectorPtr maxIds_;
   MatrixPtr maxValues_;
@@ -989,7 +1091,7 @@ REGISTER_EVALUATOR(max_id_printer, MaxIdPrinter);
  *
  * The config file api is maxframe_printer_evaluator.
  */
-class MaxFramePrinter : public Evaluator {
+class MaxFramePrinter : public NotGetableEvaluator {
 private:
   IVectorPtr maxIds_;
   MatrixPtr maxValues_;
@@ -1076,7 +1178,7 @@ REGISTER_EVALUATOR(max_frame_printer, MaxFramePrinter);
  * The config file api is seqtext_printer_evaluator.
  *
  */
-class SequenceTextPrinter : public Evaluator {
+class SequenceTextPrinter : public NotGetableEvaluator {
 private:
   /// dict_file, which contains a list of tokens
   std::vector<std::string> dict_;
@@ -1243,4 +1345,6 @@ public:
 };
 REGISTER_EVALUATOR(classification_error_printer, ClassificationErrorPrinter);
 
+std::string DummyEvaluator::getTypeImpl() const { return "dummy"; }
+
 }  // namespace paddle

paddle/gserver/evaluators/Evaluator.h

@@ -19,6 +19,7 @@ limitations under the License. */
 #include "paddle/parameter/Argument.h"
 #include "paddle/pserver/ParameterClient2.h"
 #include "paddle/utils/ClassRegistrar.h"
+#include "paddle/utils/Error.h"
 
 namespace paddle {
 
@@ -117,12 +118,105 @@ public:
 
   static ClassRegistrar<Evaluator> registrar_;
 
+  /**
+   * @brief getNames will return all field names of current evaluator.
+   *
+   * The format of name is `evaluator_name.evaluator_fields`. If the evaluator
+   * has multiple field, the name could be `evaluator_name.field1`. For example
+   * the PrecisionRecallEvaluator contains `precision`, `recall` fields. The get
+   * names will return `precision_recall_evaluator.precision`,
+   * `precision_recall_evaluator.recal`, etc.
+   *
+   * Also, if current Evaluator is a combined evaluator. getNames will return
+   * all names of all evaluators inside the combined evaluator.
+   *
+   * @param names [out]: the field names of current evaluator.
+   * @note Never clear the names parameter inside getNames.
+   */
+  virtual void getNames(std::vector<std::string>* names) {
+    names->push_back(config_.name());
+  }
+
+  /**
+   * @brief getValue will return the current evaluate value of one field.
+   *
+   * @param name: The field name of current evaluator.
+   * @param err [out]: The error state.
+   *
+   * @return The evaluate value(metric).
+   */
+  virtual real getValue(const std::string& name, Error* err) const {
+    if (name != config_.name()) {
+      *err = Error("no such name of evaluator %s", name.c_str());
+      return .0f;
+    }
+    return this->getValueImpl();
+  }
+
+  /**
+   * @brief getType will return the evaluator type by field name.
+   *
+   * Evaluate Type is the current type of evaluator in string. Such as 'auc',
+   * 'precision_recall'. In combined evaluator, different name may get different
+   * evaluate type because it could be evaluated by different evaluator inside.
+   *
+   * @param name: The field name of current Evaluator.
+   * @param err: The error state. nullptr means don't care.
+   * @return the evaluator type string.
+   */
+  virtual std::string getType(const std::string& name, Error* err) const {
+    if (name != config_.name()) {
+      *err = Error("no such name of evaluator %s", name.c_str());
+      return std::string();
+    }
+    return this->getTypeImpl();
+  }
+
+protected:
+  /**
+   * @brief getValueImpl The simplest way to define getValue result. If this
+   * evaluator doesn't contain multiple fields, and do not throw any error, just
+   * implemented this method to get the evaluate result(metric).
+   * @return Evaluate result(metric).
+   */
+  virtual real getValueImpl() const {
+    return numSamples_ != .0 ? totalScore_ / numSamples_ : .0;
+  }
+
+  /**
+   * @brief getTypeImpl The simplest way to define getType result. If this
+   * evaluator doesn't combine many evaluators, the get type should only return
+   * itself type.
+   * @return Evaluator type.
+   */
+  virtual std::string getTypeImpl() const { return "base"; }
+
 protected:
   EvaluatorConfig config_;
   double numSamples_;
   double totalScore_;
 };
 
+/**
+ * @brief The NotGetableEvaluator class is the base class of evaluator that
+ * cannot get value in runtime. The most NotGetableEvaluator is Printer
+ * Evaluator, which is only used to debug network configuration.
+ */
+class NotGetableEvaluator : public Evaluator {
+  // Evaluator interface
+public:
+  void getNames(std::vector<std::string>* names) {}
+
+  real getValue(const std::string& name, Error* err) const {
+    *err = Error("Not implemented");
+    return .0f;
+  }
+  std::string getType(const std::string& name, Error* err) const {
+    *err = Error("Not implemented");
+    return "";
+  }
+};
+
 class DummyEvaluator : public Evaluator {
 public:
   DummyEvaluator() {}
@@ -135,6 +229,10 @@ public:
   }
   virtual void finish() {}
   virtual void printStats(std::ostream&) const {}
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const;
 };
 /**
  * @brief evaluate AUC using colIdx-th column as prediction.
@@ -191,6 +289,11 @@ private:
   }
 
   double calcAuc() const;
+
+  // Evaluator interface
+protected:
+  real getValueImpl() const;
+  std::string getTypeImpl() const;
 };
 
 /**
@@ -223,6 +326,10 @@ private:
                      real* clickData,
                      real* pvData,
                      size_t size);
+
+  // Evaluator interface
+protected:
+  std::string getTypeImpl() const;
 };
 /**
  * @brief precision, recall and f1 score Evaluator
@@ -272,6 +379,20 @@ private:
   IVectorPtr cpuLabel_;
   MatrixPtr cpuWeight_;
 
+  struct PrintStatsInfo {
+    double precision;
+    double recall;
+    double f1;
+    double macroAvgPrecision;
+    double macroAvgRecall;
+    double macroAvgF1Score;
+    double microAvgPrecision;
+    double microAvgRecall;
+    double microAvgF1Score;
+  };
+
+  bool getStatsInfo(PrintStatsInfo* info) const;
+
   void calcStatsInfo(const MatrixPtr& output,
                      const IVectorPtr& label,
                      const MatrixPtr& weight);
@@ -303,6 +424,15 @@ private:
       return 0;
     }
   }
+
+  mutable std::unordered_map<std::string, real> values_;
+
+  void storeLocalValues() const;
+  // Evaluator interface
+public:
+  void getNames(std::vector<std::string>* names);
+  real getValue(const std::string& name, Error* err) const;
+  std::string getType(const std::string& name, Error* err) const;
 };
 
 /*
@@ -349,8 +479,7 @@ public:
   virtual void finish() { calc(predictArray_); }
 
   virtual void printStats(std::ostream& os) const {
-    os << " pos/neg"
-       << "=" << pairArray_[0] / ((pairArray_[1] <= 0) ? 1.0 : pairArray_[1]);
+    os << " pos/neg=" << this->getValueImpl();
   }
 
   virtual void distributeEval(ParameterClient2* client) {
@@ -366,6 +495,13 @@ private:
   IVectorPtr cpuLabel_;
   IVectorPtr cpuInfo_;
   MatrixPtr cpuWeight_;
+
+  // Evaluator interface
+protected:
+  real getValueImpl() const {
+    return pairArray_[0] / ((pairArray_[1] <= 0) ? 1.0 : pairArray_[1]);
+  }
+  std::string getTypeImpl() const;
 };
 
 }  // namespace paddle

paddle/gserver/gradientmachines/NeuralNetwork.cpp

@@ -306,7 +306,6 @@ void NeuralNetwork::onPassEnd() {
 
 class CombinedEvaluator : public Evaluator {
 public:
-  CombinedEvaluator() {}
   void addEvaluator(std::unique_ptr<Evaluator>&& evaluator) {
     evaluators_.emplace_back(std::move(evaluator));
   }
@@ -346,6 +345,55 @@ public:
 
 protected:
   std::vector<std::unique_ptr<Evaluator>> evaluators_;
+
+  // Evaluator interface
+public:
+  /**
+   * @brief getNames will return all inside evaluators' names.
+   * @param names [out]: return names.
+   */
+  void getNames(std::vector<std::string>* names) {
+    for (auto& eval : evaluators_) {
+      eval->getNames(names);
+    }
+  }
+
+  /**
+   * @brief getValue could get all inside evaluators' value.
+   */
+  real getValue(const std::string& name, Error* err) const {
+    return this->getMethodHelper<real>(
+        name, err, [&name, err](const std::unique_ptr<Evaluator>& eval) {
+          return eval->getValue(name, err);
+        });
+  }
+
+  /**
+   * @brief getType could get all inside evaluators' type.
+   */
+  std::string getType(const std::string& name, Error* err) const {
+    return this->getMethodHelper<std::string>(
+        name, err, [&name, err](const std::unique_ptr<Evaluator>& eval) {
+          return eval->getType(name, err);
+        });
+  }
+
+private:
+  template <typename T>
+  T getMethodHelper(const std::string& name,
+                    Error* err,
+                    const std::function<T(const std::unique_ptr<Evaluator>&)>&
+                        callback) const {
+    for (auto& eval : evaluators_) {
+      std::vector<std::string> names;
+      eval->getNames(&names);
+      if (std::find(names.begin(), names.end(), name) != names.end()) {
+        return callback(eval);
+      }
+    }
+    *err = Error("No such key %s", name.c_str());
+    return T();
+  }
 };
 
 Evaluator* NeuralNetwork::makeEvaluator() const {

paddle/gserver/tests/test_Evaluator.cpp

@@ -110,6 +110,18 @@ void testEvaluator(TestConfig testConf,
   testEvaluator->finish();
   LOG(INFO) << *testEvaluator;
 
+  std::vector<std::string> names;
+  testEvaluator->getNames(&names);
+  paddle::Error err;
+  for (auto& name : names) {
+    auto value = testEvaluator->getValue(name, &err);
+    ASSERT_TRUE(err.isOK());
+    LOG(INFO) << name << " " << value;
+    auto tp = testEvaluator->getType(name, &err);
+    ASSERT_TRUE(err.isOK());
+    ASSERT_EQ(testConf.evaluatorConfig.type(), tp);
+  }
+
   double totalScore2 = 0.0;
   if (testConf.testAccumulate) {
     testEvaluator->start();

paddle/utils/Error.h

@@ -37,10 +37,10 @@ namespace paddle {
  *
  * Error __must_check bar() {
  *   // do something.
- *   Status s = foo();  // invoke other method return status.
- *   if (!s) return s;
+ *   Error err = foo();  // invoke other method return status.
+ *   if (err) return err;
  *   // do something else.
- *   return Status();
+ *   return Error();
  * }
  * @endcode{cpp}
  *
@@ -53,8 +53,8 @@ namespace paddle {
  *
  * int foo(Error* error) {
  *   // Do something.
- *   Error s = bar();
- *   if (!s) {
+ *   Error err = bar();
+ *   if (err) {
  *     *error = s;
  *     return 0;
  *   }
@@ -68,10 +68,10 @@ namespace paddle {
  * }
  *
  * Error foobar() {
- *   Error s;
+ *   Error err;
  *   // do something.
- *   foo(&s);
- *   if (!s) return s;
+ *   foo(&err);
+ *   if (err) return err;
  * }
  * @endcode{cpp}
  *
@@ -112,16 +112,22 @@ public:
   }
 
   /**
-   * @brief operator bool, return True if there is no error.
+   * @brief operator bool, return True if there is something error.
    */
-  operator bool() const { return msg_ == nullptr; }
+  operator bool() const { return !this->isOK(); }
+
+  /**
+   * @brief isOK return True if there is no error.
+   * @return True if no error.
+   */
+  bool isOK() const { return msg_ == nullptr; }
 
   /**
    * @brief check this status by glog.
    * @note It is a temp method used during cleaning Paddle code. It will be
    *       removed later.
    */
-  void check() const { CHECK(*this) << msg(); }
+  void check() const { CHECK(this->isOK()) << msg(); }
 
 private:
   std::shared_ptr<std::string> msg_;

paddle/utils/tests/test_Error.cpp

@@ -18,17 +18,17 @@ limitations under the License. */
 
 TEST(Error, testAll) {
   paddle::Error error;
-  ASSERT_TRUE(error);
-  error = paddle::Error("I'm the error");
   ASSERT_FALSE(error);
+  error = paddle::Error("I'm the error");
+  ASSERT_TRUE(error);
   ASSERT_STREQ("I'm the error", error.msg());
 
   error = paddle::Error("error2");
-  ASSERT_FALSE(error);
+  ASSERT_TRUE(error);
   ASSERT_STREQ("error2", error.msg());
 
   int i = 3;
   auto error3 = paddle::Error("error%d", i);
-  ASSERT_FALSE(error3);
+  ASSERT_TRUE(error3);
   ASSERT_STREQ("error3", error3.msg());
 }