Apply a Function to Every Chunk in a StreamPress File

Sequentially reads and decodes each chunk, applies fn, and collects results.

Usage

st_map_chunks(path, fn, transpose = FALSE, threads = 0L)

Arguments

path

Path to a .spz file.

fn

Function taking (chunk, col_start, col_end) where chunk is a dgCMatrix.

transpose

Logical; if TRUE, iterate over transpose chunks (row chunks of the original matrix). Default FALSE.

threads

Integer; decode threads per chunk. Default 0 (all threads).

Value

Invisible list of results from fn.

See also

st_chunk_ranges

Examples

if (FALSE) { # \dontrun{
# Compute column sums per chunk
st_map_chunks("data.spz", function(chunk, s, e) Matrix::colSums(chunk))
} # }