1. A method to localize anomalies in a communication network, the method comprising: identifying, with a processor, a first set of abnormal nodes in the communication network; including, with the processor, respective ones of the first set of abnormal nodes having a number of normal direct descendent nodes that is less than a combined number of abnormal direct descendent nodes and indeterminate direct descendent nodes in a set of candidate nodes; and iteratively selecting, with the processor, ones of the set of candidate nodes to include in a set of root cause abnormal nodes representing sources of the anomalies in the communication network, the ones of the set of candidate nodes selected based on sizes of respective subsets of the abnormal nodes from the first set of abnormal nodes covered by the candidate nodes.