R/Sindex.R

In aiRthermo: Atmospheric Thermodynamics and Visualization

Sindex <-
function(Ps,Ts,ws,deltaP,doLog=0){
  if ( (length(Ps)!=length(Ts))
       | (length(Ps)!=length(ws)) |
       (length(Ts)!=length(ws)) ) {
    stop("Input parameters ARE wrong, Ps, Ts, ws must be the same length")
  }
  if(is.na(deltaP)==TRUE){
    stop("deltaP parameter must be different to NA")
  }
  
  N_Ps<-which(is.na(Ps)==TRUE)
  N_Ts<-which(is.na(Ts)==TRUE)
  N_ws<-which(is.na(ws)==TRUE)
  Ps[c(N_Ts,N_ws)]<-NA
  Ts[c(N_Ps,N_ws)]<-NA
  ws[c(N_Ts,N_Ps)]<-NA
  Ps2<-na.omit(Ps)
  Ts2<-na.omit(Ts)
  ws2<-na.omit(ws)
  nlevs<-length(Ts2)
  
  outvals<-.C("Sindex_Rworld",as.double(Ps2),
              as.double(Ts2),as.double(ws2),
              as.integer(nlevs),as.integer(doLog),as.double(deltaP),
	      result=double(1))

  if (outvals[["result"]]==-99999999){
    warning("Needed levels (850, 700 and 500 hPa) not found")
    return(NA)    
  } else {
    return(outvals[["result"]])  
  }

}