srowen commented on a change in pull request #23589: [SPARK-26351][mllib]Update doc and minor correction in the mllib evaluation metrics URL: https://github.com/apache/spark/pull/23589#discussion_r249256455
########## File path: docs/mllib-evaluation-metrics.md ########## @@ -462,10 +462,10 @@ $$rel_D(r) = \begin{cases}1 & \text{if $r \in D$}, \\ 0 & \text{otherwise}.\end{ <td>Normalized Discounted Cumulative Gain</td> <td> $NDCG(k)=\frac{1}{M} \sum_{i=0}^{M-1} {\frac{1}{IDCG(D_i, k)}\sum_{j=0}^{n-1} - \frac{rel_{D_i}(R_i(j))}{\text{ln}(j+2)}} \\ + \frac{rel_{D_i}(R_i(j))}{\text{log}_2(j+2)}} \\ Review comment: This isn't how it's computed, though the base won't matter. To avoid confusion, what about just writing "log" with no base? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org