Johnson-lindenstrauss Dimensionality Reduction on the Simplex

We propose an algorithm for dimensionality reduction on the simplex, mapping a set of high-dimensional distributions to a space of lower-dimensional distributions, whilst approximately preserving pairwise Hellinger distance between distributions. By introducing a restriction on the input data to distributions that are in some sense quite smooth, we can map n points on the d-simplex to the simplex of O(ε−2 log n) dimensions with ε-distortion with high probability. The techniques used rely on a classical result by Johnson and Lindenstrauss on dimensionality reduction for Euclidean point sets and require the same number of random bits as non-sparse methods proposed by Achlioptas for database-friendly dimension-