[R] Invalid term in model formula with gmm after formula.tools is loaded

[Elysée Aristide]

Hi Ivan,

Thank you for your message. Does that mean that I should send a new
message? Or is it okay for this time?

Best,
Aristide

On Fri, Nov 1, 2024, 22:29 Ivan Krylov <ikrylov using disroot.org> wrote:

> Hi Aristide and welcome to R-help!
>
> Your message was a bit mangled [*]. It's best to compose messages to
> this mailing list in plain text. Otherwise (when composed in HTML), the
> mailing list eats the HTML part and we're left with the plain text part
> automatically generated by your mailer, which isn't always readable.
>
> В Wed, 30 Oct 2024 17:45:29 +0100
> Elysée Aristide <ariel92and using gmail.com> пишет:
>
> > I am using the gmm function from the gmm package and encountered an
> > unexpected error. No model can be estimated if I load formula.tools—I
> > need to restart R each time.
>
> I can reproduce the problem:
>
> library(gmm)
> data(Finance)
> r <- Finance[1:300, 1:10]
> rm <- Finance[1:300, "rm"]
> rf <- Finance[1:300, "rf"]
> z <- as.matrix(r-rf)
> zm <- rm-rf
> res <- gmm(z ~ zm, x = ~ zm)
> library(formula.tools)
> gmm(z ~ zm, x = ~ zm) # signals an error
>
> Looking at the traceback(), I see the formula being transformed into NA
> ~ NA at some point:
>
> 10: terms.formula(formula, data = data) # <-- error happens here
> 9: terms(formula, data = data)
> 8: model.frame.default(data = object$data, formula = NA ~ NA,
> drop.unused.levels = TRUE,
>        na.action = "na.pass")
> 7: model.frame(data = object$data, formula = NA ~ NA, drop.unused.levels =
> TRUE,
>        na.action = "na.pass") # <-- formula is already NA ~ NA here
> 6: eval(mfh, parent.frame())
> 5: eval(mfh, parent.frame())
> 4: getDat(object$g, object$x, data = object$data)
> 3: getModel.baseGmm(all_args, ...)
> 2: getModel(all_args, ...)
> 1: gmm(z ~ zm, x = ~zm)
>
> It seems that in base R, as.character(z ~ zm) returns a three-element
> character vector, while with formula.tools loaded, it only returns a
> single string, 'z ~ zm'. This breaks formula manipulation in getDat().
>
> An immediate workaround is to replace the method provided by
> formula.tools with one that immediately delegates back to R:
>
> .S3method('as.character', 'formula', function (x, ...) NextMethod())
> gmm(z ~ zm, x = ~ zm) # seems to work once again
>
> (Is there a way to truly unregister an S3 method?)
>
> Perhaps gmm::getDat could be made more robust by working directly on
> the formula/call object instead of going through the string
> representation.
>
> --
> Best regards,
> Ivan
>
> [*] https://stat.ethz.ch/pipermail/r-help/2024-October/480157.html
>

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