Change functions in common.h into template functions (#969) (#973)

* Fix coding style (#969)

Function names must be in the "Pascal Case" style.

* check_elements_interval_closed to CheckElementsIntervalClosed

* obtain_min_max_sum to ObtainMinMaxSum

* Change functions in common.h into template functions (#969)

* CheckElementsIntervalClosed

* ObtainMinMaxSum

These two functions were changed into template functions.

* Remove an unpreferable overload

* remove an overload of the function ObtainMinMaxSum

* Use stringstream to format T type

include/LightGBM/utils/common.h

@@ -580,20 +580,24 @@ static void ParallelSort(_RanIt _First, _RanIt _Last, _Pr _Pred) {
 }
 
 // Check that all y[] are in interval [ymin, ymax] (end points included); throws error if not
-inline void CheckElementsIntervalClosed(const float *y, float ymin, float ymax, int ny, const char *callername) {
+template <typename T>
+inline void CheckElementsIntervalClosed(const T *y, T ymin, T ymax, int ny, const char *callername) {
   for (int i = 0; i < ny; ++i) {
     if (y[i] < ymin || y[i] > ymax) {
-      Log::Fatal("[%s]: does not tolerate element [#%i = %f] outside [%f, %f]", callername, i, y[i], ymin, ymax);
+      std::ostringstream os;
+      os << "[%s]: does not tolerate element [#%i = " << y[i] << "] outside [" << ymin << ", " << ymax << "]";
+      Log::Fatal(os.str().c_str(), callername, i);
     }
   }
 }
 
 // One-pass scan over array w with nw elements: find min, max and sum of elements;
 // this is useful for checking weight requirements.
-inline void ObtainMinMaxSum(const float *w, int nw, float *mi, float *ma, double *su) {
-  float minw = w[0];
-  float maxw = w[0];
-  double sumw = static_cast<double>(w[0]);
+template <typename T1, typename T2>
+inline void ObtainMinMaxSum(const T1 *w, int nw, T1 *mi, T1 *ma, T2 *su) {
+  T1 minw = w[0];
+  T1 maxw = w[0];
+  T2 sumw = static_cast<T2>(w[0]);
   for (int i = 1; i < nw; ++i) {
     sumw += w[i];
     if (w[i] < minw) minw = w[i];

src/metric/xentropy_metric.hpp

@@ -87,7 +87,7 @@ public:
       sum_weights_ = static_cast<double>(num_data_);
     } else {
       float minw;
-      Common::ObtainMinMaxSum(weights_, num_data_, &minw, nullptr, &sum_weights_);
+      Common::ObtainMinMaxSum(weights_, num_data_, &minw, (float*)nullptr, &sum_weights_);
       if (minw < 0.0f) {
         Log::Fatal("[%s:%s]: (metric) weights not allowed to be negative", GetName()[0].c_str(), __func__);
       }
@@ -178,7 +178,7 @@ public:
     // check all weights are strictly positive; throw error if not
     if (weights_ != nullptr) {
       float minw;
-      Common::ObtainMinMaxSum(weights_, num_data_, &minw, nullptr, nullptr);
+      Common::ObtainMinMaxSum(weights_, num_data_, &minw, (float*)nullptr, (float*)nullptr);
       if (minw <= 0.0f) {
         Log::Fatal("[%s:%s]: (metric) all weights must be positive", GetName()[0].c_str(), __func__);
       }
@@ -263,7 +263,7 @@ public:
       sum_weights_ = static_cast<double>(num_data_);
     } else {
       float minw;
-      Common::ObtainMinMaxSum(weights_, num_data_, &minw, nullptr, &sum_weights_);
+      Common::ObtainMinMaxSum(weights_, num_data_, &minw, (float*)nullptr, &sum_weights_);
       if (minw < 0.0f) {
         Log::Fatal("[%s:%s]: (metric) at least one weight is negative", GetName()[0].c_str(), __func__);
       }

src/objective/regression_objective.hpp

@@ -318,7 +318,7 @@ public:
     // Safety check of labels
     float miny;
     double sumy;
-    Common::ObtainMinMaxSum(label_, num_data_, &miny, nullptr, &sumy);
+    Common::ObtainMinMaxSum(label_, num_data_, &miny, (float*)nullptr, &sumy);
     if (miny < 0.0f) {
       Log::Fatal("[%s]: at least one target label is negative.", GetName());
     }

src/objective/xentropy_objective.hpp

@@ -58,7 +58,7 @@ public:
     if (weights_ != nullptr) {
       float minw;
       double sumw;
-      Common::ObtainMinMaxSum(weights_, num_data_, &minw, nullptr, &sumw);
+      Common::ObtainMinMaxSum(weights_, num_data_, &minw, (float*)nullptr, &sumw);
       if (minw < 0.0f) {
         Log::Fatal("[%s]: at least one weight is negative.", GetName());
       }
@@ -163,7 +163,7 @@ public:
 
     if (weights_ != nullptr) {
 
-      Common::ObtainMinMaxSum(weights_, num_data_, &min_weight_, &max_weight_, nullptr);
+      Common::ObtainMinMaxSum(weights_, num_data_, &min_weight_, &max_weight_, (float*)nullptr);
       if (min_weight_ <= 0.0f) {
         Log::Fatal("[%s]: at least one weight is non-positive.", GetName());
       }