VIKOR function from MCDM R package is returning error

Question

I am trying to run VIKOR from MCDM R package using the following code

library(MCDM)

 d <- matrix(c(1,2,5,3000,3750,4500),nrow = 3,ncol = 2)
 w <- c(0.5,0.5)
 cb <- c('min','max')
 v <- 0.5
 VIKOR(d,w,cb,v)

But it returns me following error

Error in (Q == "NaN") || (Q == "Inf") : 'length = 3' in coercion to 'logical(1)'

How can I solve this error?

The source code for VIKOR is available here.

Answer 1

I have solved this problem by modifying the source code like

VIKOR <- function(decision, #matrix with all the alternatives
                  weights,  #vector with the numeric values of the weights
                  cb,       #vector with the "type" of the criteria (benefit = "max", cost = "min")
                  v         #value with the real number of the 'v' parameter to calculate Q
)
{
  #Checking parameters
  if(! is.matrix(decision))
    stop("'decision' must be a matrix with the values of the alternatives")
  if(missing(weights))
    stop("a vector containing n weigths, adding up to 1, should be provided")
  if(sum(weights) != 1)
    stop("The sum of 'weights' is not equal to 1")
  if(! is.character(cb))
    stop("'cb' must be a character vector with the type of the criteria")
  if(! all(cb == "max" | cb == "min"))
    stop("'cb' should contain only 'max' or 'min'")
  if(length(weights) != ncol(decision))
    stop("length of 'weights' does not match the number of the criteria")
  if(length(cb) != ncol(decision))
    stop("length of 'cb' does not match the number of the criteria")
  if(missing(v))
    stop("a value for 'v' in [0,1] should be provided")
  
  #1. Ideal solutions
  posI <- as.integer(cb == "max") * apply(decision, 2, max) +
    as.integer(cb == "min") * apply(decision, 2, min)
  negI <- as.integer(cb == "min") * apply(decision, 2, max) +
    as.integer(cb == "max") * apply(decision, 2, min)
  
  #2. S and R index
  norm =function(x,w,p,n){
    w*((p-x)/(p-n))
  }
  SAux <- apply(decision, 1, norm, weights, posI, negI)
  S <- apply(SAux, 2, sum)
  R <- apply(SAux, 2, max)
  
  
  #3. Q index
  #If v=0
  if (v==0)
    Q <- (R-min(R))/(max(R)-min(R))
  #If v=1
  else if (v==1)
    Q <- (S-min(S))/(max(S)-min(S))
  #Another case
  else
    Q <- v*(S-min(S))/(max(S)-min(S))+(1-v)*(R-min(R))/(max(R)-min(R))
  
  #4. Checking if Q is valid
  #Here is the change by taking help from https://stackoverflow.com/questions/76667355/how-to-ignore-ranking-if-the-data-conatins-nan-or-inf-in-r
  RankingQ = ifelse(is.infinite(Q) | is.na(Q), NA,
         rank(Q, ties.method = "first"))
  
  #5. Ranking the alternatives
  return(data.frame(Alternatives = 1:nrow(decision), S = S, R = R, Q = Q, 
                    Ranking = RankingQ))
  
}

Now it is working fine like

d <- matrix(c(1,2,5,3000,3750,4500),nrow = 3,ncol = 2)
w <- c(0.5,0.5)
cb <- c('min','max')
v <- 0.5
VIKOR(d,w,cb,v)

#>  Alternatives     S    R Q Ranking
#> 1            1 0.500 0.50 1       2
#> 2            2 0.375 0.25 0       1
#> 3            3 0.500 0.50 1       3