R/FLHessenDecomp.R

In Fuzzy-Logix/AdapteR: Converts R syntax to SQL to provide fast analytics using in-database C++ library DB Lytix.

#' @include FLMatrix.R
NULL



#' Hessenberg Decomposition of a Matrix.
#'
#' \code{FLHessen} computes the Hessenberg decomposition for FLMatrix objects.
#'
#' @param object is of class FLMatrix
#' @param ... any additional arguments
#' @section Constraints:
#' Input can only be square matrix with maximum dimension limitations of (700 x 700). If the matrix is
#' non-symmetric FLJordan() will run slower.
#' @return \code{FLHessen} returns a list of two components:
#'       \item{P}{FLMatrix representing P matrix obtained from Hessenberg decomposition}
#'       \item{H}{FLMatrix representing H matrix obtained from Hessenberg decomposition}
#' @examples
#' flmatrix <- FLMatrix(getTestTableName("tblMatrixMulti"), 5,"MATRIX_ID","ROW_ID","COL_ID","CELL_VAL",dims= c(5,5))
#' resultList <- FLHessen(flmatrix)
#' resultList$P
#' resultList$H
#' @seealso Refer to \code{\link{FLMatrix}} to know more about FLMatrix.
#' @export
FLHessen<-function(object, ...){
	UseMethod("FLHessen",object)
}

#' @export
FLHessen.FLMatrix<-function(object,...)
{
	#checkSquare(object,"FLHessen")
	connection<-getFLConnection(object)
    ## flag1Check(connection)


    # sqlstr <- paste0(
    #                  viewSelectMatrix(object, "a","z"),
    #                  outputSelectMatrix("FLHessenbergDecompUdt",viewName="z",localName="a",
    #                 	outColNames=list("OutputMatrixID","OutputRowNum",
    #                 		"OutputColNum","OutputPVal","OutputHVal"),
    #                 	whereClause=" ")
    #                )
    
    sqlstr <- constructMatrixUDTSQL(pObject=object,
                                 pFuncName="FLHessenbergDecompUdt",
                                 pdims=getDimsSlot(object),
                                 pdimnames=dimnames(object),
                                 pReturnQuery=TRUE
                                 )
    sqlstr <- gsub("'%insertIDhere%'",1,sqlstr)
	
    sqlstr <- ensureQuerySize(pResult=sqlstr,
	            pInput=list(object),
	            pOperator="FLHessen")

    tempResultTable <- cacheDecompResults(pFuncName="FLHessenbergDecompUdt",
                                          pQuery=sqlstr)
    # tempResultTable <- createTable(pTableName=gen_unique_table_name("Hessen"),
    #                                pSelect=sqlstr)

	PMatrix <- FLMatrix(connection = connection, 
				       table_name = tempResultTable, 
					   matrix_id_value = "",
					   matrix_id_colname = "", 
					   row_id_colname = "OutputRowNum", 
					   col_id_colname = "OutputColNum", 
					   cell_val_colname = "OutputPVal",
					   whereconditions=paste0(tempResultTable,".OutputPVal IS NOT NULL ")
					   )

	HMatrix <- FLMatrix(connection = connection, 
				       table_name = tempResultTable, 
					   matrix_id_value = "",
					   matrix_id_colname = "", 
					   row_id_colname = "OutputRowNum", 
					   col_id_colname = "OutputColNum", 
					   cell_val_colname = "OutputHVal",
					   whereconditions=paste0(tempResultTable,".OutputHVal IS NOT NULL ")
		             )

		result<-list(P = PMatrix,
					 H = HMatrix)
		result
}