Re: [R] Overloading %*%

From: Spencer Graves <spencer.graves_at_pdf.com>
Date: Sun, 16 Mar 2008 15:07:24 -0700

Thanks, Ken.

  1. How can I find S4 methods for a given function given class(es) of objects? The 'showMethods' function lists available generics for a given function; "showMethods('%*%')" just produced for me a list of 52 different signatures for "%*%". However, I don't know how to find the functions with methods for a particular class. The 'methods' function will produce either S3 methods for a given function or S3 functions for a given class. It would help me if the 'methods' help page included "See Also" and "Examples" for S4 classes also, but it doesn't.
  2. How can I find source code for S4 methods? I tried "dumpMethods('%*%', 'mmult.R')" and got an apparently empty file of 0 KB. Then I tried 'dumpMethod("%*%", c(x="TsparseMatrix", y="ANY"))' and got a file with the following:

setMethod("%*%", structure(c("TsparseMatrix", "ANY"), .Names = c("x", "y")), NULL
)

      Thanks again for your reply regarding "%*%". 
      Spencer Graves   

knoblauch wrote:
> Joe Cainey <jcainey <at> gmail.com> writes:
>

>> Is it possible to supply a new method for the %*% operator? 
>>     

> clipped
>
>> I've tried to do the same thing with %*%:
>>
>> "%*%.ad" <- function(a,b)
>> {
>>     # further code here
>> }
>> However this doesn't work; the new method is never called and the standard
>> %*% operator is used instead. I've had a look at the documentation and it
>> appears to be because the %*% operator is not part of the "Math", "Ops",
>> "Summary" or "Complex" groups. I was wondering if anybody knew of a
>> work-around for this?
>>     

> According to the help page for %*%, it is S4 generic but not S3, so
> you might make further progress using S4 methods.
>

>
>> Thanks,
>>
>> Joe Cainey
>>
>>     

> best,
>

> Ken
>

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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. Received on Sun 16 Mar 2008 - 22:22:14 GMT

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