  Source code summarization is the task of generating a high-level natural
language description for a segment of programming language code. Current neural
models for the task differ in their architecture and the aspects of code they
consider. In this paper, we show that three SOTA models for code summarization
work well on largely disjoint subsets of a large code-base. This
complementarity motivates model combination: We propose three meta-models that
select the best candidate summary for a given code segment. The two neural
models improve significantly over the performance of the best individual model,
obtaining an improvement of 2.1 BLEU points on a dataset of code segments where
at least one of the individual models obtains a non-zero BLEU.
