[R] Overloading %*%

[Spencer Graves]

Dear Martin: 

      This is wonderful.  Thank you very much. 

      It would be a great help if your suggestions could be added to 
"See Also" and "Examples" for "methods". 

      Thanks again,
      Spencer Graves

Martin Morgan wrote:
> Spencer Graves wrote:
>   
>> 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 
>>     
>
> Use the 'classes' argument to showMethods, either with or without a 
> function as first argument.
>
>   
>> 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 
>>     
>
> use includeDef=TRUE with showMethods, or getMethod to get a specific 
> method, or, for some fun, selectMethod to find the method to which 
> object dispatch occurs. I'm not sure how to dump the method to a file.
>
> Martin
>
>   
>> "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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>>>
>>>       
>> ______________________________________________
>> R-help at 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 at 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.
>
>