Concurrent Evaluation of R Processes?

I am using the R nodes with KNIME 2.11 on Linux/Mac OS X.  I have noticed that only one R process runs at a time, in spite of the fact that there are no apparent dependencies between them.

Is it possible to execute these in parallel?

Short answer is no, our implementation uses plain old R, along with JRI and rJava, which means we are not threadsafe and can only execute one script at a time.  You might try using the community R nodes which work on RServe which *may* allow parallel node execution, although I have not set this up and verified it myself. 

Regards, Aaron

Yes, with the R scripting integration from the community nodes it should be possible to execute multiple R-nodes in paralell (as long as the R-server does not run on Windows).