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for each element in matrix...

2 messages · Andrej Kastrin, PIKAL Petr

Andrej Kastrin
# 
Dead R useRs,

I wrote function, which plot dotchart from given matrix, compute mean 
from diagonal elements and plot it with abline. In addition, if 
particular element of matrix is greater then mean value (i.e. 
mead.diagonal), it should be plot in red, otherwise in green color.

graph <- function(a) {
    rownames(a) <- 1:nrow(a)
    colnames(a) <- 1:ncol(a)
    mean.diagonal <- mean(a[row(a) == col(a)])
    par(bg = "gray95")
    dotchart(a, cex = 0.9, main = "MeSH Plot", xlab = "frequency",
        bg = ifelse((a) > mean.diagonal,"red", "green2"),  # !!!
            pch = 21,labels = rownames(a))
    abline(v = mean.diagonal, col = "red", lty = 4)
}

And now the main problem: I suppose that there is some mismatch in 
ifelse statement while I produce two totally different plots:
first input matrix:  A <-matrix(rep(c(1,3,4),3),3,3) # seem that works
second input matrix B <-matrix(rnorm(9),3,3) # total confusion between 
green and red points

Any advice would be appreciated,

Cheers, Andrej
PIKAL Petr
# 
Hi

a bit of organisetion in colour sequence will do it.

graph1 <- function(a) {
    rownames(a) <- 1:nrow(a)
    colnames(a) <- 1:ncol(a)
    mean.diagonal <- mean(diag(a))

 bar<-c("red","green")[(a>mean(diag(a)))+1]
 bar<-matrix(bar[9:1],3,3)[3:1,]  # you need to set these according # 
# to actual dimensions of your matrices e.g. 
# bar<-matrix(bar[length(a):1],dim(a)[1],dim(a)[2])[dim(a)[1]:1,]

    par(bg = "gray95")
    dotchart(a, cex = 0.9, main = "MeSH Plot", xlab = "frequency",
        bg = bar,  # !!!
            pch = 21,labels = rownames(a))
    abline(v = mean.diagonal, col = "red", lty = 4)
}

HTH
Petr
On 5 Feb 2006 at 21:21, Andrej Kastrin wrote:
Date sent:      	Sun, 05 Feb 2006 21:21:20 +0100
From:           	Andrej Kastrin <andrej.kastrin at siol.net>
To:             	R-help <r-help at stat.math.ethz.ch>
Subject:        	[R] for each element in matrix...
Petr Pikal
petr.pikal at precheza.cz