  Link prediction aims to uncover missing links or predict the emergence of
future relationships according to the current networks structure. Plenty of
algorithms have been developed for link prediction in unweighted networks, with
only a very few of them having been extended to weighted networks. Thus far,
how to predict weights of links is important but rarely studied. In this
Letter, we present a reliable-route-based method to extend unweighted local
similarity indices to weighted indices and propose a method to predict both the
link existence and link weights accordingly. Experiments on different real
networks suggest that the weighted resource allocation index has the best
performance to predict the existence of links, while the reliable-route-based
weighted resource allocation index performs noticeably better on weight
prediction. Further analysis shows a strong correlation for both link
prediction and weight prediction: the larger the clustering coefficient, the
higher the prediction accuracy.
