looking for a better way to code a bar graph

I've just used r a little, so  this might be a trivial question but



I have a small  data file

part,   vs/total         ,ps/total,    gpgpu,   date

...       ...               ...             ...           ..



that contains the percent that certain features contribute to a part and
the date the part was built





I'd like to do stacked bar graphs one bar per part showing the percents

and  I'd like tospace the bars based on the date released



I tried



area <- read.csv("c:/talks/pact2008/g1.csv");

dates <-strptime(as.character(area$date), "%m/%d/%Y")



##  hack to figure out the amount to shift the bars

l  <- length(as.POSIXct(dates))

diff <- as.numeric(difftime(dates[2:l], dates[1:(l-1)]))

diff <- rev(diff/max(diff))



colors <- gray.colors(3)





data <- c(area$ps.total[1:5], area$vs.total[1:5], area$gpgpu[1:5])



data <- 100*t(matrix(data, 5, 3))



## the .6 makes the bars look a little lighter, I did ths by eye

barplot(data,  space=diff+.6)







This works giving me the graph I want, but it seems so clunky, what is a
better way?





I do get a warning



Warning messages:

1: In space + width :

 longer object length is not a multiple of shorter object length

2: In space + width :

 longer object length is not a multiple of shorter object length

making me think I'm not understanding how space works.  I don't
understand how to set width, what kind of units would it be in?




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