From 206f3cdbe0454c695a72c969c527bda3cdc8a4b3 Mon Sep 17 00:00:00 2001
From: Tianqi Chen <tianqi.tchen@gmail.com>
Date: Mon, 4 May 2015 11:13:14 -0700
Subject: [PATCH] msvc

---
 src/utils/math.h | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/utils/math.h b/src/utils/math.h
index 06612b1a8..e0bf8c466 100644
--- a/src/utils/math.h
+++ b/src/utils/math.h
@@ -6,11 +6,7 @@
  * \author Tianqi Chen
  */
 #include <cmath>
-#ifdef _MSC_VER
-extern "C" {
-#include <amp_math.h>
-}
-#endif
+
 namespace xgboost {
 namespace utils {
 #ifdef XGBOOST_STRICT_CXX98_
@@ -21,14 +17,24 @@ double LogGamma(double v);
 template<typename T>
 inline bool CheckNAN(T v) {
 #ifdef _MSC_VER
-  return (_isnan(x) != 0);
+  return (_isnan(v) != 0);
 #else
   return isnan(v);
 #endif
 }
 template<typename T>
 inline T LogGamma(T v) {
+#ifdef _MSC_VER
+#if _MSC_VER >= 1800
   return lgamma(v);
+#else
+#pragma message ("Warning: lgamma function was not available until VS2013, poisson regression will be disabled")
+  utils::Error("lgamma function was not available until VS2013");
+  return static_cast<T>(1.0);
+#endif
+#else
+  return lgamma(v);
+#endif
 }
 #endif
 }  // namespace utils