For those who have the same question later....after following John's steps of extracting the function, I just replaced the line of code that says:
if ((!ignore.double) || (heads[par] == 1)) with if (((!ignore.double) || (heads[par] == 1)) & variables[from[par]] != variables[to[par]]) That seems to do just what I want. Thanks again John! On Wed, Nov 9, 2011 at 5:40 PM, Dustin Fife <fife.dus...@gmail.com> wrote: > Perfect! Thanks for the help. > > On Wed, Nov 9, 2011 at 4:27 PM, John Fox <j...@mcmaster.ca> wrote: >> Dear Dustin, >> >>> -----Original Message----- >>> From: Dustin Fife [mailto:fife.dus...@gmail.com] >>> Sent: November-09-11 2:12 PM >>> To: John Fox >>> Cc: r-help@r-project.org >>> Subject: Re: [R] path.diagram in SEM--display covariances without >>> variances >>> >>> Thanks for the quick response...I've never edited someone else's >>> package before. How do I go about doing that? >> >> I wouldn't change the sem package, but rather create your own version of >> pathDiagram(). You could examine the package sources, but, more simply, to >> see the code for the function, type its name at the command prompt: >> >>> library(sem) >> Loading required package: MASS >> Loading required package: matrixcalc >>> pathDiagram >> function (model, ...) >> { >> UseMethod("pathDiagram") >> } >> <bytecode: 0000000006E1CEA8> >> <environment: namespace:sem> >> >> So pathDiagram() is a generic function. What methods are available? >> >>> methods(pathDiagram) >> [1] pathDiagram.sem* >> >> Non-visible functions are asterisked >> >> There is, therefore just one method, for objects of class "sem", hidden in >> the sem namespace. To see it (most lines elided): >> >>> sem:::pathDiagram.sem >> function (model, file, min.rank = NULL, max.rank = NULL, same.rank = NULL, >> variables = model$var.names, parameters = rownames(model$ram), >> ignore.double = TRUE, edge.labels = c("names", "values", >> "both"), size = c(8, 8), node.font = c("Helvetica", 14), >> edge.font = c("Helvetica", 10), rank.direction = c("LR", >> "TB"), digits = 2, standardize = FALSE, output.type = c("graphics", >> "dot"), graphics.fmt = "pdf", dot.options = NULL, ...) >> { >> . . . >> cat(file = handle, "}\n") >> if (output.type == "graphics" && !missing(file)) { >> cmd <- paste("dot -T", graphics.fmt, " -o ", graph.file, >> " ", dot.options, " ", dot.file, sep = "") >> cat("Running ", cmd, "\n") >> result <- try(system(cmd)) >> } >> invisible(NULL) >> } >> <bytecode: 00000000071B9568> >> <environment: namespace:sem> >> >> Just copy the functions into an editor and make whatever changes you want. >> >> Best, >> John >> >>> >>> On Wed, Nov 9, 2011 at 12:47 PM, John Fox <j...@mcmaster.ca> wrote: >>> > Dear Dustin, >>> > >>> >> -----Original Message----- >>> >> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- >>> >> project.org] On Behalf Of Dustin Fife >>> >> Sent: November-09-11 10:57 AM >>> >> To: r-help@r-project.org >>> >> Subject: [R] path.diagram in SEM--display covariances without >>> >> variances >>> >> >>> >> Forgive me if I'm posting to the wrong place....It's my first time >>> >> posting. >>> >> >>> >> Here's the situation: I'm using the sem package and making path >>> >> diagrams using path.diagrams. Suppose I have the following code: >>> >> >>> > . . . >>> > >>> >> The diagram is produces is hard to read because of the many >>> variances >>> >> that are shown. The covariance estimates are important for my >>> >> diagram, but the variances are not. Is there a way to suppress the >>> >> variance arrows without suppressing the covariance arrows? >>> > >>> > No, but (1) pathDiagram() (the name of the function in the current >>> > version of the sem package) produces an editable text file, from >>> which >>> > you could remove the arrows that you don't want to see; and (2) you >>> > could modify >>> > pathDiagram() -- the code for the function is, after all, available >>> to >>> > you >>> > -- so that it does what you want. >>> > >>> > I hope this helps, >>> > John >>> > >>> > -------------------------------- >>> > John Fox >>> > Senator William McMaster >>> > Professor of Social Statistics >>> > Department of Sociology >>> > McMaster University >>> > Hamilton, Ontario, Canada >>> > http://socserv.mcmaster.ca/jfox >>> > >>> > >>> > >>> >> >>> >> -- >>> >> Dustin Fife >>> >> Graduate Student, Quantitative Psychology University of Oklahoma >>> >> >>> >> ______________________________________________ >>> >> R-help@r-project.org mailing list >>> >> 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. >>> > >>> > >>> >>> >>> >>> -- ______________________________________________ R-help@r-project.org mailing list 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.
