else if (position < indexlessData.length)
newIndexless.add(indexlessData[position]);
else
newData.add(data[position - indexlessData.length]);
}
return new Product(new IndicesBuilder().append(newData).getIndices(), newFactor,
newIndexless.toArray(new Tensor[newIndexless.size()]),
newData.toArray(new Tensor[newData.size()]));
}