Bug in package stats function ar() (PR#10459)

Steven McKinney wrote:

Full_Name: Steven McKinney
Version: 2.6.0
OS: OS X
Submission from: (NULL) (142.103.207.10)



Function ar() in package "stats" is showing
a quirky bug.  Some calls to ar() run to
completion, others throw an error.

The bug is reproducible by several people on different
machines, however, the ar() function itself ends
up throwing the error sporadically.  Several calls to
ar() may be necessary to trip the error condition.

Code to reproduce:

x<-ts(c(-0.2052083,-0.3764986,-0.3762448,0.3740089,0.2737568,2.8235722,-1.7783313,0.2728676,-0.3273164),start=c(1978,3),frequency=4,end=c(1980,3))
# ar function
res.ar<-ar(x,aic=TRUE,demean=F)
# call "ar" again and ............
res.ar<-ar(x,aic=TRUE,demean=F)


Example output:
(Note that on this attempt the first call to ar()
 tripped the error.)

x<-ts(c(-0.2052083,-0.3764986,-0.3762448,0.3740089,0.2737568,2.8235722,-

+
1.7783313,0.2728676,-0.3273164),start=c(1978,3),frequency=4,end=c(1980,3))

 Slightly more detail: in the "eureka" function, in stats/src/eureka.f, the
last
element of "vars" in the return list is bogus and varies among calls; if it
comes out to NaN or NA it triggers the bug.

  Haven't spent any more time yet tracking this down, but hope that
will save someone a few minutes.