diff --git a/hikyuu_cpp/hikyuu/StockManager.cpp b/hikyuu_cpp/hikyuu/StockManager.cpp
index 51285c4e..381a30cd 100644
--- a/hikyuu_cpp/hikyuu/StockManager.cpp
+++ b/hikyuu_cpp/hikyuu/StockManager.cpp
@@ -133,9 +133,8 @@ void StockManager::init(
 
 
 void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
-    string funcname(" [StockManager::setKDataDriver]");
     if (!driver) {
-        HKU_ERROR("kdata driver is null!" << funcname);
+        HKU_ERROR("kdata driver is null! [StockManager::setKDataDriver]");
         return;
     }
 
@@ -149,7 +148,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_day = m_preloadParam.get<bool>("day");
         if (preload_day)
-            HKU_INFO("Preloading all day kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all day kdata to buffer!");
     } catch(...) {
         preload_day = false;
     }
@@ -158,7 +157,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_week = m_preloadParam.get<bool>("week");
         if (preload_week)
-            HKU_INFO("Preloading all week kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all week kdata to buffer!");
     } catch(...) {
         preload_week = false;
     }
@@ -167,7 +166,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_month = m_preloadParam.get<bool>("month");
         if (preload_week)
-            HKU_INFO("Preloading all month kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all month kdata to buffer!");
     } catch(...) {
         preload_month = false;
     }
@@ -176,7 +175,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_quarter = m_preloadParam.get<bool>("quarter");
         if (preload_quarter)
-            HKU_INFO("Preloading all quarter kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all quarter kdata to buffer!");
     } catch(...) {
         preload_quarter = false;
     }
@@ -185,7 +184,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_halfyear = m_preloadParam.get<bool>("halfyear");
         if (preload_halfyear)
-            HKU_INFO("Preloading all halfyear kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all halfyear kdata to buffer!");
     } catch(...) {
         preload_halfyear = false;
     }
@@ -194,7 +193,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_year = m_preloadParam.get<bool>("year");
         if (preload_year)
-            HKU_INFO("Preloading all year kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all year kdata to buffer!");
     } catch(...) {
         preload_year = false;
     }
@@ -203,7 +202,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_min = m_preloadParam.get<bool>("min");
         if (preload_min)
-            HKU_INFO("Preloading all 1 min kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all 1 min kdata to buffer!");
     } catch(...) {
         preload_min = false;
     }
@@ -212,7 +211,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_min5 = m_preloadParam.get<bool>("min5");
         if (preload_min5)
-            HKU_INFO("Preloading all 5 min kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all 5 min kdata to buffer!");
     } catch(...) {
         preload_min5 = false;
     }
@@ -221,7 +220,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_min15 = m_preloadParam.get<bool>("min15");
         if (preload_min15)
-            HKU_INFO("Preloading all 15 min kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all 15 min kdata to buffer!");
     } catch(...) {
         preload_min15 = false;
     }
@@ -230,7 +229,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_min30 = m_preloadParam.get<bool>("min30");
         if (preload_min30)
-            HKU_INFO("Preloading all 30 min kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all 30 min kdata to buffer!");
     } catch(...) {
         preload_min30 = false;
     }
@@ -239,7 +238,7 @@ void StockManager::setKDataDriver(const KDataDriverPtr& driver) {
     try {
         preload_min60 = m_preloadParam.get<bool>("min60");
         if (preload_min60)
-            HKU_INFO("Preloading all 60 min kdata to buffer!" << funcname);
+            HKU_INFO("Preloading all 60 min kdata to buffer!");
     } catch(...) {
         preload_min60 = false;
     }
diff --git a/hikyuu_cpp/hikyuu/indicator/Indicator.cpp b/hikyuu_cpp/hikyuu/indicator/Indicator.cpp
index 1ccbc57f..a36c14c6 100644
--- a/hikyuu_cpp/hikyuu/indicator/Indicator.cpp
+++ b/hikyuu_cpp/hikyuu/indicator/Indicator.cpp
@@ -84,6 +84,22 @@ Indicator Indicator::clone() const {
     return m_imp ? Indicator(m_imp->clone()) : Indicator();
 }
 
+PriceList Indicator::getResultAsPriceList(size_t num) const {
+    if (!m_imp) {
+        HKU_WARN("indicator imptr is null! [Indicator::getResultAsPriceList]");
+        return PriceList();
+    }
+    return m_imp->getResultAsPriceList(num);
+}
+
+Indicator Indicator::getResult(size_t num) const {
+    if (!m_imp) {
+        HKU_WARN("indicator imptr is null! [Indicator::getResult]");
+        return Indicator();
+    }
+    return m_imp->getResult(num);
+}
+
 Indicator Indicator::operator()(const Indicator& ind) {
     if (!m_imp)
         return Indicator();
@@ -92,7 +108,7 @@ Indicator Indicator::operator()(const Indicator& ind) {
         return Indicator(m_imp);
     
     IndicatorImpPtr p = m_imp->clone();
-    p->add(IndicatorImp::OP, IndicatorImpPtr(), ind.getImp()->clone());
+    p->add(IndicatorImp::OP, IndicatorImpPtr(), ind.getImp());
     return p->calculate();
 }
 
@@ -102,7 +118,7 @@ HKU_API Indicator operator+(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::ADD, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::ADD, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -112,7 +128,7 @@ HKU_API Indicator operator-(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::SUB, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::SUB, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -122,7 +138,7 @@ HKU_API Indicator operator*(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::MUL, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::MUL, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -132,7 +148,7 @@ HKU_API Indicator operator/(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::DIV, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::DIV, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -142,7 +158,7 @@ HKU_API Indicator operator==(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::EQ, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::EQ, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -152,7 +168,7 @@ HKU_API Indicator operator!=(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::NE, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::NE, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -162,7 +178,7 @@ HKU_API Indicator operator>(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::GT, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::GT, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -172,7 +188,7 @@ HKU_API Indicator operator<(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::LT, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::LT, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -182,7 +198,7 @@ HKU_API Indicator operator>=(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::GE, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::GE, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -192,7 +208,7 @@ HKU_API Indicator operator<=(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::LE, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::LE, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -202,7 +218,7 @@ HKU_API Indicator operator&(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::AND, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::AND, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
@@ -212,7 +228,7 @@ HKU_API Indicator operator|(const Indicator& ind1, const Indicator& ind2) {
     }
 
     IndicatorImpPtr p = make_shared<IndicatorImp>();
-    p->add(IndicatorImp::OR, ind1.getImp()->clone(), ind2.getImp()->clone());
+    p->add(IndicatorImp::OR, ind1.getImp(), ind2.getImp());
     return p->calculate();
 }
 
diff --git a/hikyuu_cpp/hikyuu/indicator/Indicator.h b/hikyuu_cpp/hikyuu/indicator/Indicator.h
index cff6725d..fb3a189a 100644
--- a/hikyuu_cpp/hikyuu/indicator/Indicator.h
+++ b/hikyuu_cpp/hikyuu/indicator/Indicator.h
@@ -86,6 +86,13 @@ public:
      * @note 不做下标越界检查，也不抛出异常
      */
     price_t operator[](size_t pos) const {
+#if CHECK_ACCESS_BOUND
+        if (!m_imp) {
+            throw(std::out_of_range(
+                "Try to access empty indicator! [Indicator::get]"));
+            return Null<price_t>();
+        }
+#endif        
         return m_imp->get(pos, 0);
     }
 
@@ -96,16 +103,19 @@ public:
      * @note 不做下标越界检查，不会抛出异常
      */
     price_t get(size_t pos, size_t num = 0) const {
+#if CHECK_ACCESS_BOUND
+        if (!m_imp) {
+            throw(std::out_of_range(
+                "Try to access empty indicator! [Indicator::get]"));
+            return Null<price_t>();
+        }
+#endif        
         return m_imp->get(pos, num);
     }
 
-    Indicator getResult(size_t num) const {
-        return m_imp->getResult(num);
-    }
+    Indicator getResult(size_t num) const;
 
-    PriceList getResultAsPriceList(size_t num) const {
-        return m_imp->getResultAsPriceList(num);
-    }
+    PriceList getResultAsPriceList(size_t num) const;
 
     template <typename ValueType>
     void setParam(const string& name, const ValueType& value) {
diff --git a/hikyuu_cpp/hikyuu/indicator/IndicatorImp.cpp b/hikyuu_cpp/hikyuu/indicator/IndicatorImp.cpp
index f5f2b8dc..21f625c5 100644
--- a/hikyuu_cpp/hikyuu/indicator/IndicatorImp.cpp
+++ b/hikyuu_cpp/hikyuu/indicator/IndicatorImp.cpp
@@ -296,8 +296,8 @@ void IndicatorImp::add(OPType op, IndicatorImpPtr left, IndicatorImpPtr right) {
     }
 
     m_optype = op;
-    m_left = left;
-    m_right = new_right ? new_right : right;
+    m_left = left ? left->clone() : left;
+    m_right = new_right ? new_right : right->clone();
 }
 
 Indicator IndicatorImp::calculate() {
diff --git a/hikyuu_cpp/hikyuu/indicator/IndicatorImp.h b/hikyuu_cpp/hikyuu/indicator/IndicatorImp.h
index 70afd776..5e346541 100644
--- a/hikyuu_cpp/hikyuu/indicator/IndicatorImp.h
+++ b/hikyuu_cpp/hikyuu/indicator/IndicatorImp.h
@@ -8,6 +8,7 @@
 #ifndef INDICATORIMP_H_
 #define INDICATORIMP_H_
 
+#include "../config.h"
 #include "../KData.h"
 #include "../utilities/Parameter.h"
 #include "../utilities/util.h"
@@ -79,6 +80,13 @@ public:
     }
 
     price_t get(size_t pos, size_t num = 0) {
+#if CHECK_ACCESS_BOUND
+        if ((m_pBuffer[num] == NULL) || pos>= m_pBuffer[num]->size()) {
+            throw(std::out_of_range("Try to access value out of bounds! "
+                        + name() + " [IndicatorImp::get]"));
+            return Null<price_t>();
+        }
+#endif
         return (*m_pBuffer[num])[pos];
     }
 
@@ -95,11 +103,8 @@ public:
     void _set(price_t val, size_t pos, size_t num = 0) {
 #if CHECK_ACCESS_BOUND
         if ((m_pBuffer[num] == NULL) || pos>= m_pBuffer[num]->size()) {
-            std::stringstream err_info;
-            err_info << "Try to access value out of bounds! "
-                     << name() << " [IndicatorImp::_set]";
-            HKU_FATAL(err_info.str());
-            throw(std::out_of_range(err_info.str()));
+            throw(std::out_of_range("Try to access value out of bounds! "
+                        + name() + " [IndicatorImp::_set]"));
             return;
         }
         (*m_pBuffer[num])[pos] = val;
diff --git a/hikyuu_cpp/hikyuu/indicator/imp/IKData.cpp b/hikyuu_cpp/hikyuu/indicator/imp/IKData.cpp
index a6704a60..b9cf0ab0 100644
--- a/hikyuu_cpp/hikyuu/indicator/imp/IKData.cpp
+++ b/hikyuu_cpp/hikyuu/indicator/imp/IKData.cpp
@@ -42,6 +42,10 @@ bool IKData::check() {
 void IKData::_calculate(const Indicator& ind) {
     KData kdata = getCurrentKData();
     size_t total = kdata.size();
+    if (total == 0) {
+        return;
+    }
+    
     string part_name = getParam<string>("kpart");
     
     if ("KDATA" == part_name) {
diff --git a/hikyuu_cpp/hikyuu/indicator/imp/ILiuTongPan.cpp b/hikyuu_cpp/hikyuu/indicator/imp/ILiuTongPan.cpp
index 7f151c1b..bca48e58 100644
--- a/hikyuu_cpp/hikyuu/indicator/imp/ILiuTongPan.cpp
+++ b/hikyuu_cpp/hikyuu/indicator/imp/ILiuTongPan.cpp
@@ -29,6 +29,10 @@ bool ILiuTongPan::check() {
 void ILiuTongPan::_calculate(const Indicator& data) {
     KData k = getCurrentKData();
     size_t total = k.size();
+    if (total == 0) {
+        return;
+    }
+    
     _readyBuffer(total, 1);
 
     if (total == 0) {