Enable chunk-wise processing for all peaks data functions

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: Spectra
 Title: Spectra Infrastructure for Mass Spectrometry Data
-Version: 1.13.1
+Version: 1.13.2
 Description: The Spectra package defines an efficient infrastructure
    for storing and handling mass spectrometry spectra and functionality to
    subset, process, visualize and compare spectra data. It provides different

NAMESPACE

@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+export("processingChunkSize<-")
 export(MsBackendCached)
 export(MsBackendDataFrame)
 export(MsBackendHdf5Peaks)
@@ -27,6 +28,8 @@ export(plotMzDelta)
 export(plotSpectra)
 export(plotSpectraOverlay)
 export(ppm)
+export(processingChunkFactor)
+export(processingChunkSize)
 export(processingLog)
 export(reduceSpectra)
 export(scalePeaks)
@@ -63,6 +66,7 @@ exportMethods(addProcessing)
 exportMethods(backendBpparam)
 exportMethods(backendInitialize)
 exportMethods(backendMerge)
+exportMethods(backendParallelFactor)
 exportMethods(bin)
 exportMethods(c)
 exportMethods(centroided)

NEWS.md

@@ -1,5 +1,17 @@
 # Spectra 1.13
 
+## Changes in 1.13.2
+
+- Add possibility to enable and perform chunk-wise (parallel) processing to
+  `Spectra`: add functions `processingChunkSize`, `backendParallelFactor` and
+  `processingChunkFactor` to set or get definition of chunks for parallel
+  processing. All functions working on peaks data use this mechanism which
+  is implemented in the internal `.peaksapply` function. The `Spectra` object
+  gains a new slot `"processingChunkSize"` that is used to define the
+  size of the processing chunks for the `Spectra`. See also [issue
+  #304](https://github.com/rformassspectrometry/Spectra/issues/304).
+  This ensures processing also of very large data sets.
+
 ## Changes in 1.13.1
 
 - Fix issue with `bin` function (see

R/AllGenerics.R

@@ -11,6 +11,9 @@ setGeneric("backendMerge", def = function(object, ...)
     standardGeneric("backendMerge"),
     valueClass = "MsBackend")
 #' @rdname hidden_aliases
+setGeneric("backendParallelFactor", def = function(object, ...)
+    standardGeneric("backendParallelFactor"))
+#' @rdname hidden_aliases
 setMethod("bin", "numeric", MsCoreUtils::bin)
 setGeneric("combinePeaks", function(object, ...)
            standardGeneric("combinePeaks"))

R/MsBackend.R

@@ -9,6 +9,8 @@
 #' @aliases supportsSetBackend
 #' @aliases backendBpparam
 #' @aliases backendInitialize
+#' @aliases backendParallelFactor,MsBackendMzR-method
+#' @aliases backendParallelFactor,MsBackendHdf5Peaks-method
 #'
 #' @description
 #'
@@ -212,7 +214,9 @@
 #'   because they contain a connection to a database that can not be
 #'   shared across processes) should extend this method to return only
 #'   `SerialParam()` and hence disable parallel processing for (most)
-#'   methods and functions.
+#'   methods and functions. See also `backendParallelFactor` for a
+#'   function to provide a preferred splitting of the backend for parallel
+#'   processing.
 #'
 #' - `backendInitialize`: initialises the backend. This method is
 #'   supposed to be called rights after creating an instance of the
@@ -233,6 +237,14 @@
 #'   instance. All objects to be merged have to be of the same type (e.g.
 #'   [MsBackendDataFrame()]).
 #'
+#' - `backendParallelFactor`: returns a `factor` defining an optimal
+#'   (preferred) way how the backend can be split for parallel processing
+#'   used for all peak data accessor or data manipulation functions.
+#'   The default implementation returns a factor of length 0 (`factor()`)
+#'   providing thus no default splitting. A `backendParallelFactor` for
+#'   `MsBackendMzR` on the other hand returns `factor(dataStorage(object))`
+#'   hence suggesting to split the object by data file.
+#'
 #' - `dataOrigin`: gets a `character` of length equal to the number of spectra
 #'   in `object` with the *data origin* of each spectrum. This could e.g. be
 #'   the mzML file from which the data was read.
@@ -849,6 +861,13 @@ setMethod("backendMerge", "MsBackend", function(object, ...) {
     stop("Not implemented for ", class(object), ".")
 })
 
+#' @exportMethod backendParallelFactor
+#'
+#' @rdname MsBackend
+setMethod("backendParallelFactor", "MsBackend", function(object, ...) {
+    factor()
+})
+
 #' @rdname MsBackend
 setMethod("export", "MsBackend", function(object, ...) {
     stop(class(object), " does not support export of data; please provide a ",

R/MsBackendHdf5Peaks.R

@@ -306,3 +306,7 @@ setMethod("backendMerge", "MsBackendHdf5Peaks", function(object, ...) {
     validObject(res)
     res
 })
+
+setMethod("backendParallelFactor", "MsBackendHdf5Peaks", function(object) {
+    factor(dataStorage(object), levels = unique(dataStorage(object)))
+})

R/MsBackendMzR.R

@@ -210,3 +210,7 @@ setMethod("export", "MsBackendMzR", function(object, x, file = tempfile(),
                     MoreArgs = list(format = format, copy = copy),
                     BPPARAM = BPPARAM)
 })
+
+setMethod("backendParallelFactor", "MsBackendMzR", function(object) {
+    factor(dataStorage(object), levels = unique(dataStorage(object)))
+})