downsampleMatrix returns sparse when it should return dense result

[mschubert]

The ?scuttle::downsampleMatrix documentation states:

By default, the output format will be a dense matrix for an ordinary matrix ‘x’, and a sparse matrix for any sparse format (i.e., if ‘is_sparse(x)’ returns ‘TRUE’).

However, I get a sparse result for a dense input in scuttle_1.14.0:

scuttle::downsampleMatrix(matrix(1000), prop=0.5)
# 1 x 1 sparse Matrix of class "dgCMatrix"
#
# [1,] 500

It seems that either the behavior or the documentation is wrong here.

[LTLA]

The documentation I see in ?downsampleMatrix is

An numeric matrix-like object of downsampled counts. This is a dgCMatrix unless ‘sink’ is set, in which case it is a DelayedMatrix.

Session info

R version 4.4.1 Patched (2024-06-20 r86796)
Platform: aarch64-apple-darwin22.6.0
Running under: macOS Ventura 13.6.9

Matrix products: default
BLAS:   /Users/luna/Software/R/R-4-4-branch/lib/libRblas.dylib
LAPACK: /Users/luna/Software/R/R-4-4-branch/lib/libRlapack.dylib;  LAPACK version 3.12.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

time zone: America/Los_Angeles
tzcode source: internal

attached base packages:
[1] stats4    stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
 [1] scuttle_1.15.4              SingleCellExperiment_1.27.2
 [3] SummarizedExperiment_1.35.2 Biobase_2.65.1
 [5] GenomicRanges_1.57.1        GenomeInfoDb_1.41.1
 [7] IRanges_2.39.2              S4Vectors_0.43.2
 [9] BiocGenerics_0.51.2         MatrixGenerics_1.17.0
[11] matrixStats_1.4.1

loaded via a namespace (and not attached):
 [1] crayon_1.5.3            httr_1.4.7              UCSC.utils_1.1.0
 [4] jsonlite_1.8.9          DelayedArray_0.31.12    grid_4.4.1
 [7] abind_1.4-8             compiler_4.4.1          codetools_0.2-20
[10] Rcpp_1.0.13             XVector_0.45.0          BiocParallel_1.39.0
[13] lattice_0.22-6          R6_2.5.1                SparseArray_1.5.41
[16] parallel_4.4.1          GenomeInfoDbData_1.2.13 Matrix_1.7-0
[19] tools_4.4.1             beachmat_2.21.6         zlibbioc_1.51.1
[22] S4Arrays_1.5.9

[mschubert]

the details description is there in git head

[LTLA]

Looks like that part of the documentation didn't get updated in 5b2ce63. Perhaps you can put together a PR with the fix, otherwise I'll get to it when I have some spare time.