Running examples in ‘mlr-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: benchmark
> ### Title: Benchmark experiment for multiple learners and tasks.
> ### Aliases: benchmark
> 
> ### ** Examples
> 
> lrns = list(makeLearner("classif.lda"), makeLearner("classif.rpart"))
> tasks = list(iris.task, sonar.task)
> rdesc = makeResampleDesc("CV", iters = 2L)
> meas = list(acc, ber)
> bmr = benchmark(lrns, tasks, rdesc, measures = meas)
Task: iris-example, Learner: classif.lda
Resampling: cross-validation
Measures:             acc       ber       
[Resample] iter 1:    0.9600000 0.0401235 
[Resample] iter 2:    1.0000000 0.0000000 


Aggregated Result: acc.test.mean=0.9800000,ber.test.mean=0.0200617


Task: Sonar-example, Learner: classif.lda
Resampling: cross-validation
Measures:             acc       ber       
[Resample] iter 1:    0.6538462 0.3470218 
[Resample] iter 2:    0.7211538 0.2972264 


Aggregated Result: acc.test.mean=0.6875000,ber.test.mean=0.3221241


Task: iris-example, Learner: classif.rpart
Resampling: cross-validation
Measures:             acc       ber       
[Resample] iter 1:    0.9333333 0.0679012 
[Resample] iter 2:    0.8400000 0.1555184 


Aggregated Result: acc.test.mean=0.8866667,ber.test.mean=0.1117098


Task: Sonar-example, Learner: classif.rpart
Resampling: cross-validation
Measures:             acc       ber       
[Resample] iter 1:    0.6730769 0.3303737 
[Resample] iter 2:    0.7307692 0.2953523 


Aggregated Result: acc.test.mean=0.7019231,ber.test.mean=0.3128630


> rmat = convertBMRToRankMatrix(bmr)
> print(rmat)
              Sonar-example iris-example
classif.lda               2            1
classif.rpart             1            2
> plotBMRSummary(bmr)
Error in grid.Call.graphics(C_setviewport, vp, TRUE) : 
  VECTOR_ELT() can only be applied to a 'list', not a 'double'
Calls: <Anonymous> ... push.vp.vpTree -> push.vp -> push.vp.viewport -> grid.Call.graphics
Execution halted