From 74b9f7cb88cd21cfac3c2e50c8efb802485df0c5 Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Fri, 29 May 2015 23:06:58 +0800
Subject: init

---
 tnet_io/KaldiLib/MathAux.h | 117 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 tnet_io/KaldiLib/MathAux.h

(limited to 'tnet_io/KaldiLib/MathAux.h')

diff --git a/tnet_io/KaldiLib/MathAux.h b/tnet_io/KaldiLib/MathAux.h
new file mode 100644
index 0000000..c08e836
--- /dev/null
+++ b/tnet_io/KaldiLib/MathAux.h
@@ -0,0 +1,117 @@
+#ifndef TNet_MathAux_h
+#define TNet_MathAux_h
+
+#include <cmath>
+
+
+#if !defined(SQR)
+# define SQR(x) ((x) * (x))
+#endif
+
+
+#if !defined(LOG_0)
+# define LOG_0 (-1.0e10)
+#endif
+
+#if !defined(LOG_MIN)
+# define LOG_MIN   (0.5 * LOG_0)
+#endif
+
+
+#ifndef DBL_EPSILON
+#define DBL_EPSILON 2.2204460492503131e-16
+#endif
+
+
+#ifndef M_PI
+#  define M_PI 3.1415926535897932384626433832795
+#endif
+
+#define M_LOG_2PI 1.8378770664093454835606594728112
+
+
+#if DOUBLEPRECISION
+#  define FLOAT double
+#  define EPSILON DBL_EPSILON
+#  define FLOAT_FMT "%lg"
+#  define swapFLOAT swap8
+#  define _ABS  fabs
+#  define _COS  cos
+#  define _EXP  exp
+#  define _LOG  log
+#  define _SQRT sqrt
+#else
+#  define FLOAT float
+#  define EPSILON FLT_EPSILON
+#  define FLOAT_FMT "%g"
+#  define swapFLOAT swap4
+#  define _ABS  fabsf
+#  define _COS  cosf
+#  define _EXP  expf
+#  define _LOG  logf
+#  define _SQRT sqrtf
+#endif
+
+namespace TNet
+{
+  inline float frand(){ // random between 0 and 1.
+	return (float(rand()) + 1.0f) / (float(RAND_MAX)+2.0f);
+  }
+  inline float gauss_rand(){
+	return _SQRT( -2.0f * _LOG(frand()) ) * _COS(2.0f*float(M_PI)*frand());
+  }
+  
+  static const double gMinLogDiff = log(DBL_EPSILON);
+  
+  //***************************************************************************
+  //***************************************************************************
+  inline double
+  LogAdd(double x, double y)
+  {
+    double diff;
+  
+    if (x < y) {
+      diff = x - y;
+      x = y;
+    } else {
+      diff = y - x;
+    }
+  
+    double res;
+    if (x >= LOG_MIN) {
+      if (diff >= gMinLogDiff) {
+        res = x + log(1.0 + exp(diff));
+      } else {
+        res = x;
+      }
+    } else {
+      res = LOG_0;
+    }
+    return res;
+  } 
+
+
+  //***************************************************************************
+  //***************************************************************************
+  inline double
+  LogSub(double x, double y) // returns exp(x) - exp(y).  Throws exception if y>=x.
+  {
+
+    if(y >= x){
+      if(y==x)  return LOG_0;
+      else throw std::runtime_error("LogSub: cannot subtract a larger from a smaller number.");
+    }
+
+    double diff = y - x;  // Will be negative.
+    
+    double res = x + log(1.0 - exp(diff));
+
+    if(res != res) // test for res==NaN.. could happen if diff ~0.0, so 1.0-exp(diff) == 0.0 to machine precision.
+      res = LOG_0;
+    return res;
+  } 
+
+} // namespace TNet
+
+
+#endif
-- 
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