Contents

1 Overview

The alabaster.matrix package implements methods to save matrix-like objects to file artifacts and load them back into R. Check out the alabaster.base for more details on the motivation and the alabaster framework.

2 Quick start

Given an array-like object, we can use stageObject() to save it inside a staging directory:

library(Matrix)
y <- rsparsematrix(1000, 100, density=0.05)

library(alabaster.matrix)
tmp <- tempfile()
dir.create(tmp)
meta <- stageObject(y, tmp, "my_sparse_matrix")

library(alabaster.base)
.writeMetadata(meta, tmp)
## $type
## [1] "local"
## 
## $path
## [1] "my_sparse_matrix/matrix.h5"
list.files(tmp, recursive=TRUE)
## [1] "my_sparse_matrix/matrix.h5"      "my_sparse_matrix/matrix.h5.json"

We then load it back into our R session with loadObject(). This creates a HDF5-backed DelayedArray that can be easily coerced into the desired format, e.g., a dgCMatrix.

meta <- acquireMetadata(tmp, "my_sparse_matrix/matrix.h5")
roundtrip <- loadObject(meta, tmp)
class(roundtrip)
## [1] "H5SparseMatrix"
## attr(,"package")
## [1] "HDF5Array"

This process is supported for all base arrays, Matrix objects and DelayedArray objects.

3 Saving delayed operations

For DelayedArrays, we may instead choose to save the delayed operations themselves to file, using the chihaya package. This creates a HDF5 file following the chihaya format, containing the delayed operations rather than the results of their evaluation.

library(DelayedArray)
y <- DelayedArray(rsparsematrix(1000, 100, 0.05))
y <- log1p(abs(y) / 1:100) # adding some delayed ops.

preserveDelayedOperations(TRUE)
meta <- stageObject(y, tmp, "delayed")
.writeMetadata(meta, tmp)
## $type
## [1] "local"
## 
## $path
## [1] "delayed/delayed.h5"
meta <- acquireMetadata(tmp, "delayed/delayed.h5")
roundtrip <- loadObject(meta, tmp)
class(roundtrip)
## [1] "DelayedMatrix"
## attr(,"package")
## [1] "DelayedArray"

However, it is probably best to avoid preserving delayed operations for file-backed DelayedArrays if you want the artifacts to be re-usable on different filesystems. For example, HDF5Arrays will be saved with a reference to an absolute file path, which will not be portable.

Session information

sessionInfo()
## R version 4.3.0 RC (2023-04-13 r84269)
## Platform: x86_64-pc-linux-gnu (64-bit)
## Running under: Ubuntu 22.04.2 LTS
## 
## Matrix products: default
## BLAS:   /home/biocbuild/bbs-3.17-bioc/R/lib/libRblas.so 
## LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.10.0
## 
## locale:
##  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
##  [3] LC_TIME=en_GB              LC_COLLATE=C              
##  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
##  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
##  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
## 
## time zone: America/New_York
## tzcode source: system (glibc)
## 
## attached base packages:
## [1] stats4    stats     graphics  grDevices utils     datasets  methods  
## [8] base     
## 
## other attached packages:
##  [1] DelayedArray_0.26.0    IRanges_2.34.0         S4Vectors_0.38.0      
##  [4] MatrixGenerics_1.12.0  matrixStats_0.63.0     BiocGenerics_0.46.0   
##  [7] alabaster.base_1.0.0   alabaster.matrix_1.0.0 Matrix_1.5-4          
## [10] BiocStyle_2.28.0      
## 
## loaded via a namespace (and not attached):
##  [1] cli_3.6.1               knitr_1.42              rlang_1.1.0            
##  [4] xfun_0.39               chihaya_1.0.0           jsonlite_1.8.4         
##  [7] V8_4.3.0                htmltools_0.5.5         sass_0.4.5             
## [10] rmarkdown_2.21          grid_4.3.0              evaluate_0.20          
## [13] jquerylib_0.1.4         fastmap_1.1.1           alabaster.schemas_1.0.0
## [16] Rhdf5lib_1.22.0         yaml_2.3.7              bookdown_0.33          
## [19] jsonvalidate_1.3.2      BiocManager_1.30.20     compiler_4.3.0         
## [22] Rcpp_1.0.10             rhdf5filters_1.12.0     rhdf5_2.44.0           
## [25] lattice_0.21-8          digest_0.6.31           R6_2.5.1               
## [28] curl_5.0.0              HDF5Array_1.28.0        bslib_0.4.2            
## [31] tools_4.3.0             cachem_1.0.7