diff --git a/core/src/main/java/net/librec/math/structure/VectorBasedSequentialSparseVector.java b/core/src/main/java/net/librec/math/structure/VectorBasedSequentialSparseVector.java
index e109a4a5c..591e84367 100644
--- a/core/src/main/java/net/librec/math/structure/VectorBasedSequentialSparseVector.java
+++ b/core/src/main/java/net/librec/math/structure/VectorBasedSequentialSparseVector.java
@@ -62,7 +62,7 @@ public VectorBasedSequentialSparseVector(Vector other) {
 			List<Double> nonZeros = new ArrayList<Double>();
 			for (VectorEntry e : other) {
 				double value = e.get();
-				if (value != 0d && value != Double.NaN) {
+				if (value != 0d && !Double.isNaN(value)) {
 					nonZeros.add(value);
 				}
 			}
@@ -93,7 +93,7 @@ private OrderedIntDoubleMapping copySortedRandomAccessSparseVector(Vector other)
 		// get nonZero values
 		for (VectorEntry vectorEntry : other) {
 			double value = vectorEntry.get();
-			if (value != 0d && value != Double.NaN) {
+			if (value != 0d && !Double.isNaN(value)) {
 				sortableEntries[elementIndex++] = new OrderedVectorElement(vectorEntry.index(), value);
 			}
 		}