* @return The semantic vector generated from the circular convolution.
*/
private DoubleVector groupConvolution(Queue<String> prevWords,
Queue<String> nextWords) {
// Generate an empty DoubleVector to hold the convolution.
DoubleVector result = new DenseVector(indexVectorSize);
// Do the convolutions starting at index 0.
String prevWord = prevWords.peek();
DoubleVector tempConvolution;
if (!prevWord.equals(IteratorFactory.EMPTY_TOKEN)) {