diff --git a/include/Algo/Histogram/histogram.h b/include/Algo/Histogram/histogram.h
index feb971f336fe97269d43644481aacea7726e83d4..4406f3eff738cc8c6fd0e1d7a2a11dc513ac2e64 100644
--- a/include/Algo/Histogram/histogram.h
+++ b/include/Algo/Histogram/histogram.h
@@ -25,6 +25,10 @@
 #ifndef __HISTOGRAM__
 #define __HISTOGRAM__
 
+#define _USE_MATH_DEFINES
+#include <cmath>
+
+
 #include "Topology/generic/attributeHandler.h"
 #include "Topology/generic/cellmarker.h"
 #include "Geometry/vector_gen.h"
diff --git a/src/Algo/Histogram/histogram.cpp b/src/Algo/Histogram/histogram.cpp
index 9eddd9b43da056d6c2c090b430024db17fb9489f..c0a7cf63a4b95fc79a6d5458daa55fa5a2ea4dff 100644
--- a/src/Algo/Histogram/histogram.cpp
+++ b/src/Algo/Histogram/histogram.cpp
@@ -60,7 +60,7 @@ void Histogram::populateHisto(unsigned int nbclasses)
 {
 	//compute nb classes if necesary
 	if (nbclasses == 0)
-		m_nbclasses = (unsigned int)(sqrt(m_dataIdx.size()));
+		m_nbclasses = (unsigned int)(sqrt(double(m_dataIdx.size())));
 	else
 		m_nbclasses = nbclasses;