R/addLatent.R

In ftree: Fault Trees and Event Trees for Risk and Reliability Analysis

# addLatent.R
# copyright 2015-2016, openreliability.org
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

addLatent<-function(DF, at, mttf=NULL, mttr=NULL, prob="repair", inspect=NULL, name="",description="")  {

	if(length(names(DF))!=19)   stop("first argument must be a fault tree")
	ftree_test<-NULL
	FT_FIELDS<-getFT_FIELDS()
	for(nm in 1:18) {ftree_test<-c(ftree_test,names(DF)[nm]==FT_FIELDS[nm])}
	if(!all(ftree_test))   stop("first argument must be a fault tree")

	tp<-2
	parent<-which(DF$ID== at)
	if(length(parent)==0) {stop("connection reference not valid")}
	thisID<-max(DF$ID)+1
	if(DF$Type[parent]<10) {stop("non-gate connection requested")}
	## ***Caution Child positions in DF may change ***
	availableconn<-which(DF[parent,8:12]<1)
	if(length(availableconn)>3) {
		DF[parent,(7+availableconn[1])]<-thisID
	}else{
		if((DF$Type[parent]==10||DF$Type[parent]==11)&&length(availableconn)>0)  {
			DF[parent,(7+availableconn[1])]<-thisID
		}else{
			stop("connection slot not available")
		}
	}


	## if(tp==2)  {  ##  type condition removed
	if(is.null(mttf))  {stop("dormant component must have mttf")}
	if(is.null(mttr)) { mttr<- (-1)}

	if(is.null(inspect))  {stop("dormant component must have inspection entry")}

	if(is.null(prob)) {prob<- (-1)}
	if(is.character(inspect))  {
		if(exists("inspect")) {
			T<-eval((parse(text=inspect)))
		}else{
			stop("inspection interval object does not exist")
		}
	}else{
		T=inspect
	}

	## default Pzero handling
	if(prob=="repair")  {
		if(!mttr>0)  {stop("mttr required for probability entry")}
		prob=mttr/(mttf+mttr)
	}

	## fractional downtime method
	pf<-1-1/((1/mttf)*T)*(1-exp(-(1/mttf)*T))
	if(is.numeric(prob))  {
		if(prob>=0 && prob<1) {
			pf<- 1-(1-pf)*(1-prob)
		}else{ stop("probability entry must be between zero and one")}
	}

	Dfrow<-data.frame(
		ID= thisID  ,
		Name=   name    ,
		Parent= at  ,
		Type=   tp  ,
		CFR=    1/mttf  ,
		PBF=    pf  ,
		CRT=    mttr    ,
		Child1= -1  ,
		Child2= -1  ,
		Child3= -1  ,
		Child4= -1  ,
		Child5= -1  ,
		Level=  DF$Level[parent]+1  ,
		Independent=    TRUE    ,
		PHF=    -1  ,
		Repairable= TRUE    ,
		inspectionInterval= -1  ,
		InspectIonObject=   ""  ,
		Description=    description
		)


	DF<-rbind(DF, Dfrow)
	DF
}