[R] Using package ROCR

William Doane wd213355 at albany.edu
Thu Feb 26 09:07:53 CET 2009



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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