#'
#' @title matrixInvertDS serverside assign function called by ds.matrixInvert
#' @description Inverts a square matrix A and writes the output to the serverside
#' @details Undertakes standard matrix inversion. This operation is only
#' possible if the number of columns and rows of A are the same and the matrix
#' is non-singular - positive definite (eg there is no row or column that is all zeros)
#' @param M1.name A character string specifying the name of the matrix to be inverted
#' @return Output is the matrix representing the inverse of A which is written
#' to the serverside. For more details see help for ds.matrixInvert
#' @author Paul Burton for DataSHIELD Development Team
#' @export
#'
matrixInvertDS <- function(M1.name=NULL){
#########################################################################
# DataSHIELD MODULE: CAPTURE THE nfilter SETTINGS #
thr<-dsBase::listDisclosureSettingsDS() #
#nfilter.tab<-as.numeric(thr$nfilter.tab) #
#nfilter.glm<-as.numeric(thr$nfilter.glm) #
#nfilter.subset<-as.numeric(thr$nfilter.subset) #
#nfilter.string<-as.numeric(thr$nfilter.string) #
nfilter.stringShort<-as.numeric(thr$nfilter.stringShort) #
#nfilter.kNN<-as.numeric(thr$nfilter.kNN) #
#datashield.privacyLevel<-as.numeric(thr$datashield.privacyLevel) #
#########################################################################
#Check length of M1.name not so long as to provide a risk of hidden code
length.M1.name<-length(unlist(strsplit(M1.name,'')))
if(length.M1.name>nfilter.stringShort)
{
studysideMessage<-
paste0("FAILED: M1.name is too long it could hide concealed code, please shorten to <= nfilter.stringShort = ",
nfilter.stringShort," characters")
stop(studysideMessage, call. = FALSE)
}
#EVAL M1
M1<-eval(parse(text=M1.name), envir = parent.frame())
if(!is.matrix(M1)&&!is.data.frame(M1))
{
studysideMessage<-"FAILED: M1 must be of class matrix or data.frame, please respecify"
stop(studysideMessage, call. = FALSE)
}
#coerce to matrix if a data.frame
if(is.data.frame(M1))
{
M1<-as.matrix(M1)
}
#Check dimensions valid
if(ncol(M1)!=nrow(M1))
{
studysideMessage<-"FAILED: invalid dimensions M1 must be square: ncol must equal nrow, please respecify"
stop(studysideMessage, call. = FALSE)
}
#Check can be inverted (not singular)
if(det(M1)==0.000)
{
studysideMessage<-"FAILED: matrix singular so cannot be inverted, please respecify"
stop(studysideMessage, call. = FALSE)
}
output<-solve(M1)
return(output)
}
#ASSIGN FUNCTION
# matrixInvertDS
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