Subsample queries from a dataset

Draws rows from x and adds light Gaussian noise (sd 0.05). Querying an index with the rows it was built from flatters it: every query has an exact hit at distance zero. This puts the queries near the data instead of on it. The data is cast to f32 first, as in the Python bindings.

Usage

subsample_queries(x, n, seed = 42L)

Arguments

x

Numeric matrix, samples x features.

n

Integer. Number of rows to draw, capped at nrow(x).

seed

Integer. Random seed for the draw and the noise.

Value

Numeric matrix with min(n, nrow(x)) rows and ncol(x) columns.

Examples

dat <- generate_clustered_data(1000L, 16L)$data
query <- subsample_queries(dat, 100L)