[Perf] Optimize memory usage by reserve the capacity of vector manually.

Author: phreer

include/sample_entropy_calculator.h

@@ -87,7 +87,7 @@ class SampleEntropyCalculator {
 protected:
   virtual void _ComputeSampleEntropy() = 0;
   virtual std::string _Method() const = 0;
-  const vector<T> _data;
+  const vector<T> &_data;
   const T _r;
   unsigned K;
   const unsigned _n;

include/utils.h

@@ -36,6 +36,10 @@
   MSG(stderr, "ERROR", "File: %s, line: %d\n", __FILE__, __LINE__);            \
   exit((error_code));
 
+#define MSG_WARNING(error_code, fmt, ...)                                      \
+  MSG(stderr, "WARNING", (fmt), ##__VA_ARGS__);                                \
+  MSG(stderr, "WARNING", "File: %s, line: %d\n", __FILE__, __LINE__);
+
 #ifdef DEBUG
 #define MSG_DEBUG(fmt, ...) MSG(stdout, "DEBUG", (fmt), ##__VA_ARGS__);
 #else
@@ -83,8 +87,8 @@ double ComputeSampen(double A, double B, unsigned N, unsigned m);
 /**
  * @brief Read data from file.
  *
- * @param filename: The name of the file to read.
- * @return Read data.
+ * @param[out] result where to store the read result
+ * @param filename the name of the file to read
  */
 template <typename T>
 void ReadData(std::vector<T> &result, std::string filename,
@@ -317,34 +321,42 @@ void ReadData(std::vector<T> &result, std::string filename,
     exit(-1);
   }
   unsigned org_n = n;
-  if (n == 0)
-    n = std::numeric_limits<unsigned>::max();
+  if (n == 0) {
+    n = 1024 * 1024;
+  } else {
+    result.reserve(n);
+    result.resize(n);
+  }
   unsigned count = 0;
+  unsigned result_i = 0;
   T x = 0;
   if (input_type == "simple") {
     while (count < n + line_offset && ifs >> x) {
-      if (count >= line_offset)
-        result.push_back(x);
+      if (count >= line_offset) {
+        result[result_i] = x;
+        ++result_i;
+      }
       ++count;
     }
   } else if (input_type == "multirecord") {
     std::string line;
     while (count < n + line_offset && std::getline(ifs, line)) {
       std::istringstream iss(line);
       if (!(iss >> x >> x)) {
-        std::cerr << "Input file foramt error. \n";
-        exit(-1);
+        MSG_ERROR(-1, "Input file foramt error.\n");
+      }
+      if (count >= line_offset) {
+        result[result_i] = x;
+        ++result_i;
       }
-      if (count >= line_offset)
-        result.push_back(x);
       ++count;
     }
   } else {
     MSG_ERROR(-1, "Invalid input-type: %s\n", input_type.c_str());
   }
   if (org_n && org_n != result.size()) {
-    MSG_ERROR(-1, "Cannot read %u element from file %s. Only %zu read.\n",
-              org_n, filename.c_str(), result.size());
+    MSG_WARNING(-1, "Cannot read %u element from file %s. Only %zu read.\n",
+                org_n, filename.c_str(), result.size());
   }
   ifs.close();
 }

src/fast_sampen.cpp

@@ -284,9 +284,7 @@ template <typename T> void SampleEntropyN0N1() {
               arg.line_offset);
   unsigned n = data.size();
   if (n <= K) {
-    std::cerr << "Data length n " << n << " is too short (K = " << K;
-    std::cerr << "). \n";
-    exit(-1);
+    MSG_ERROR(-1, "Data length n %d is to short (K = %d).\n", n, K);
   }
 
   double var = ComputeVariance(data);