--- 
+++ 
@@ -29,7 +29,7 @@
             throw new DimensionMismatchException(vals.length, dim);
         }
 
-        return FastMath.pow(2 * FastMath.PI, -dim / 2) *
+return FastMath.pow(2 * FastMath.PI, -dim / 2.0) *
             FastMath.pow(covarianceMatrixDeterminant, -0.5) *
             getExponentTerm(vals);
     }