Round has unexpected behaviour about datacomparer HOT 5 CLOSED

# Create two random variables ; b is equal to a with noise added
a <- runif(100)
b <- a + runif(100)*1E-8

# Do they match?
sum(a==b) # 0

for(i in 1:10) {
  mtch <- sum(round(a,i) == round(b,i))
  print(paste0("i = ", i, " : matches = ", mtch))
}

library(dataCompareR)

dfa <- as.data.frame(a)
dfb <- as.data.frame(b)
names(dfa) <- "COL1"
names(dfb) <- "COL1"


for(i in 1:10) {
  rcmp <- rCompare(dfa, dfb, roundDigits = i)
  mtchs <- if(is.null(nrow(rcmp$mismatches$COL1))) {
        100 
    } else {
      100 - nrow(rcmp$mismatches$COL1)
    }
    
  print(paste0("datacomp : i = ", i, " : matches = ", mtchs))
}

}

[1] "i = 1 : matches = 100"
[1] "i = 2 : matches = 100"
[1] "i = 3 : matches = 100"
[1] "i = 4 : matches = 100"
[1] "i = 5 : matches = 100"
[1] "i = 6 : matches = 100"
[1] "i = 7 : matches = 96"
[1] "i = 8 : matches = 56"
[1] "i = 9 : matches = 4"
[1] "i = 10 : matches = 0"

Running rCompare...
[1] "datacomp : i = 1 : matches = 100"
Running rCompare...
[1] "datacomp : i = 2 : matches = 100"
Running rCompare...
[1] "datacomp : i = 3 : matches = 100"
Running rCompare...
[1] "datacomp : i = 4 : matches = 100"
Running rCompare...
[1] "datacomp : i = 5 : matches = 100"
Running rCompare...
[1] "datacomp : i = 6 : matches = 100"
Running rCompare...
[1] "datacomp : i = 7 : matches = 96"
Running rCompare...
[1] "datacomp : i = 8 : matches = 56"
Running rCompare...
[1] "datacomp : i = 9 : matches = 4"
Running rCompare...
[1] "datacomp : i = 10 : matches = 0"

a <- runif(100)
b <- runif(100)
c <- runif(100)
d <- runif(100)

a2 <- a +  runif(100)*1E-8
b2 <- b +  runif(100)*1E-8
c2 <- c +  runif(100)*1E-8
d2 <- d +  runif(100)*1E-8

df1 <- data.frame(a,b,c,d)
df2 <- data.frame(a2,b2,c2,d2)
names(df2) <- names(df1)

for(i in 1:15) {
  rcmp <- rCompare(df1, df2, roundDigits = i)
  mtchsa <- if(is.null(nrow(rcmp$mismatches$A))) {
    100 
  } else {
    100 - nrow(rcmp$mismatches$A)
  }
  
  mtchsb <- if(is.null(nrow(rcmp$mismatches$B))) {
    100 
  } else {
    100 - nrow(rcmp$mismatches$B)
  }
  
  mtchsc <- if(is.null(nrow(rcmp$mismatches$C))) {
    100 
  } else {
    100 - nrow(rcmp$mismatches$C)
  }
  
  mtchsd <- if(is.null(nrow(rcmp$mismatches$D))) {
    100 
  } else {
    100 - nrow(rcmp$mismatches$D)
  }
  
  print(paste0("datacomp : i = ", i, " : matches = ", mtchsa, " , ", mtchsb, " , ", mtchsc , " , ", mtchsd))
}

Running rCompare...
[1] "datacomp : i = 1 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 2 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 3 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 4 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 5 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 6 : matches = 100 , 100 , 100 , 100"
Running rCompare...
[1] "datacomp : i = 7 : matches = 94 , 93 , 96 , 96"
Running rCompare...
[1] "datacomp : i = 8 : matches = 49 , 51 , 54 , 47"
Running rCompare...
[1] "datacomp : i = 9 : matches = 2 , 6 , 8 , 4"
Running rCompare...
[1] "datacomp : i = 10 : matches = 0 , 0 , 2 , 1"
Running rCompare...
[1] "datacomp : i = 11 : matches = 0 , 0 , 0 , 0"
Running rCompare...
[1] "datacomp : i = 12 : matches = 0 , 0 , 0 , 0"
Running rCompare...
[1] "datacomp : i = 13 : matches = 0 , 0 , 0 , 0"
Running rCompare...
[1] "datacomp : i = 14 : matches = 0 , 0 , 0 , 0"
Running rCompare...
[1] "datacomp : i = 15 : matches = 0 , 0 , 0 , 0"