Minor docfixes for the inferred perplexity.

include/qdtsne/Options.hpp

@@ -17,14 +17,15 @@ struct Options {
      * Higher perplexities will focus on global structure, at the cost of increased runtime and decreased local resolution.
      *
      * This option affects all `initialize()` methods except if precomputed neighbor search results are supplied _and_ `Options::infer_perplexity = true`.
-     * In such cases, the perplexity is inferred from the number of neighbors per point in the supplied search results.
+     * In such cases, the perplexity is inferred from the number of neighbors in the supplied search results.
      */
     double perplexity = 30;
 
     /**
      * Whether to infer the perplexity in `initialize()` methods that accept a `NeighborList` object.
      * In such cases, the value in `Options::perplexity` is ignored.
-     * The perplexity is instead defined from the `NeighborList` as the number of nearest neighbors per point divided by 3.
+     * The perplexity is instead defined from the `NeighborList` as the number of nearest neighbors for the first point divided by 3.
+     * (It is assumed that all points have the same number of neighbors.)
      */
     bool infer_perplexity = true;
 

include/qdtsne/initialize.hpp

@@ -77,7 +77,7 @@ Status<num_dim_, Index_, Float_> initialize(NeighborList<Index_, Float_> nn, Flo
  * @param neighbors List of indices and distances to nearest neighbors for each observation. 
  * Each observation should have the same number of neighbors, sorted by increasing distance, which should not include itself.
  * @param options Further options.
- * If `Options::infer_perplexity = true`, the perplexity is determined from `nn` and the value in `Options::perplexity` is ignored.
+ * If `Options::infer_perplexity = true`, the perplexity is determined from `neighbors` and the value in `Options::perplexity` is ignored.
  *
  * @return A `Status` object representing an initial state of the t-SNE algorithm.
  */