Okay, that was just my reading of the help page. I hope that I haven't
added to the confusion.
Jim
On Fri, Sep 17, 2021 at 10:50 AM H <age...@meddatainc.com> wrote:
>
> On 09/15/2021 09:40 PM, Jim Lemon wrote:
> > Oops, your plot
> >
> > On Thu, Sep 16, 2021 at 11:39 AM Jim Lemon <drjimle...@gmail.com> wrote:
> >> Hi H,
> >> Looking at your example and the help page, it looks to me as though
> >> the plot is consistent with the "A" matrix:
> >>
> >> Oz
> >> Rain Nice
> >> Rain 0.25 0.75
> >> Nice 0.60 0.40
> >>
> >> # help page
> >> A - square coefficient matrix, specifying the links (rows=to, cols=from).
> >>
> >> In your plot (attached):
> >> Rain (col) goes to Rain (row) 0.25
> >> Rain (col) goes to Nice (row) 0.6
> >> Nice (col) goes to Nice (row) 0.4
> >> Nice (col) goes to Rain (row) 0.75
> >>
> >> This is a bit confusing, but it seems to do what it says it does.
> >>
> >> Jim
> >>
> >> On Thu, Sep 16, 2021 at 10:40 AM H <age...@meddatainc.com> wrote:
> >>> I am using plotmat 1.6.5 (part of the diagram package) in R 3.6 to plot
> >>> Markov transition charts but have run into an issue that I was hoping
> >>> someone could shed light on here. I did e-mail the maintainer over a
> >>> month ago but have not received a reply.
> >>>
> >>> The issue is that the directional arrows point in the wrong direction. A
> >>> brief example:
> >>>
> >>> stateNames <- c("Rain", "Nice")
> >>> Oz <- matrix(c(0.25, 0.75, 0.6, 0.4), nrow = 2, byrow = TRUE)
> >>> rownames(Oz) <- stateNames; colnames(Oz) <- stateNames
> >>> plotmat(Oz, pos = c(1, 1), lwd = 1, box.lwd = 2, cex.txt = 0.8, box.size
> >>> = 0.1, box.type = "circle", box.prop = 0.5, box.col = "light yellow",
> >>> arr.length = 0.2, arr.width = 0.2, self.cex = 0.4, self.shifty = 0.01,
> >>> self.shiftx = 0.13, main = "")
> >>>
> >>> In the above example both arrows seem to point in the direction opposite
> >>> to what I expect. Has anyone encountered this and know how to fix it?
> >>>
> >>> Thanks.
> >>>
> >>> ______________________________________________
> >>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >>> https://stat.ethz.ch/mailman/listinfo/r-help
> >>> PLEASE do read the posting guide
> >>> http://www.R-project.org/posting-guide.html
> >>> and provide commented, minimal, self-contained, reproducible code.
>
> I am sorry but I think you have it wrong. A transition probability matrix for
> the rain/nice scenario would be written:
>
> Rain, Nice
>
> Rain |0.25, 0.75|
>
> Nice |0.60, 0.40|
>
> If you sum the transition probabilities for rain or nice, they should each
> add to 1. Logic dictates if the only two states are rain and nice, and rain
> continues the next day with a probability of 0.25, nice must have a
> probability of 0.75. Likewise, the sum of probabilities for nice weather to
> change to rain, 0.6, and remain the same, 0.4 must add up to 1.
>
> I find that the arrow directions are the opposite of what I expect.
>
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