[R] Using package ROCR

wiener30 ekliokys at yahoo.com
Thu Feb 26 10:13:58 CET 2009


Thank you very much for the response!

The plot(1,1) helped to resolve the first problem.
But I am still getting a second error message when running demo(ROCR)

Error in as.double(y) : 
  cannot coerce type 'S4' to vector of type 'double'

It seems it has something to do with compatibility of S4 objects.

My versions of R and ROCR package are the same as you listed.
But it seems something other is missing in my installation.


William Doane wrote:
> 
> 
> Responding to question 1... it seems the demo assumes you already have a
> plot window open.
> 
>   library(ROCR)
>   plot(1,1)
>   demo(ROCR)
> 
> seems to work.
> 
> For question 2, my environment produces the expected results... plot
> doesn't generate an error:
>   * R 2.8.1 GUI 1.27 Tiger build 32-bit (5301)
>   * OS X 10.5.6
>   * ROCR 1.0-2
> 
> -Wil
> 
> 
> 
> wiener30 wrote:
>> 
>> I am trying to use package ROCR to analyze classification accuracy,
>> unfortunately there are some problems right at the beginning.
>> 
>> Question 1) 
>> When I try to run demo I am getting the following error message
>>> library(ROCR)
>>> demo(ROCR)
>>> if(dev.cur() <= 1) .... [TRUNCATED] 
>> Error in get(getOption("device")) : wrong first argument
>> When I issue the command
>>> dev.cur() 
>> it returns
>> null device 
>>           1
>> It seems something is wrong with my R-environment ?
>> Could somebody provide a hint, what is wrong.
>> 
>> Question 2)
>> When I run an example commands from the manual
>> library(ROCR)
>> data(ROCR.simple)
>> pred <- prediction( ROCR.simple$predictions, ROCR.simple$labels )
>> perf <- performance( pred, "tpr", "fpr" )
>> plot( perf )
>> 
>> the plot command issues the following error message
>> Error in as.double(y) : 
>>   cannot coerce type 'S4' to vector of type 'double'
>> 
>> How this could be fixed ?
>> 
>> Thanks for the support
>> 
>> 
> 
> 

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