[R] Benchmarking package, dea.plot.transform

[John P. Burkett]

The Benchmarking package is generally working well for me but one of its 
functions, dea.plot.transform, produces results that look odd to me.

Under Ubuntu 10.04 LTS, I am running R version 2.13.2 and Benchmarking 
version 0.20 ($Revision: 118 $). In that environment, I tried executing 
the following code:
y1 = c(0, 2, 6, 8)
y2 = c(7, 4, 5, 0)
library(Benchmarking)
dea.plot.transform(y1, y2)

My expectation was that the code would produce a continuous, 
piecewise-linear transformation curve (production possibility frontier) 
passing through the points (0, 7), (6, 5), and (8, 0).  Instead, it 
produced a horizontal line segment from (0, 7) to  (6, 7) and a separate 
line segment from (6, 5) to (8, 0).  The discontinuity appears to me to 
be a mistake.

If anyone could help me understand why my code is not producing the 
expected transformation curve and how to correct the problem, I would be 
most grateful.

Best regards,
John

-- 
John P. Burkett
Department of Economics
University of Rhode Island
Kingston, RI 02881-0808
USA

phone (401) 874-9195