Someone ambitious could find problems like
this using random input testing like I talked
about at useR last summer.
http://www.burns-stat.com/pages/Present/random_input_test_annotated.pdf
Testing graphics would be more labor intensive
than the testing I do, but you could think of it
as a video game.
On 17/11/2011 00:29, Duncan Murdoch wrote:
On 11-11-16 5:26 PM, Ben Bolker wrote:
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> On 11-11-16 05:18 PM, peter dalgaard wrote:
>>
>> On Nov 16, 2011, at 22:38 , Ben Bolker wrote:
>>
>>> Someone inquired on StackOverflow about apparently non-deterministic
>>> graphics behaviour in R. I noticed that they were using cex="*" and
>>> discovered some potentially weird behavior.
>>
>> It can be reproduced much more simply (well, not the hang, but bad
>> enough):
>>
>> In a plain R application console (OSX Snow Leopard),
>>
>> for (i in 1:100) plot(1:10,cex="*")
>>
>> will _sometimes_ show big circles, indicating random data being
>> picked up.
>>
>> The "cex" is by definition numeric, so you can't expect to be able to
>> pass a character string, but the code should check.
>
> Looks (?) like the check could go in FixupCex (which already tests for
> isReal, isInteger, and isLogical) in src/main/plot.c , unless there is a
> wish to catch it earlier/in R code.
Yes, that's where the check was missed. I'll fix it. The other
parameters appear to have been checked properly.
> It's mildly surprising to me that people can continue to find odd
> cases like this after more than 10 years (and imagine how many
> cumulative hours of R use ...) [I'm assuming that this hole has been
> present for a log time: I don't have the patience to do the SVN
> archaeology to find out how long.]
So now you can prove me wrong about the other parameters...
Duncan Murdoch
>
>>
>>>
>>> On repeated runs of the same code I can get different PNGs. If I set
>>> the number of runs high enough, I seem to be able to get R to hang.
>>> If I do a single version plotting to an interactive graphics window I
>>> can get the point sizes to jump around as I resize the window (someone
>>> reported being able to reproduce that behaviour in the Windows GUI
>>> as well).
>>>
>>> This is clearly a user error, but non-deterministic behaviour (and
>>> hanging) are a little disturbing.
>>>
>>> I haven't had a chance yet to try to dig in and see what's happening
>>> but thought I would report to see if anyone else could
reproduce/figure
>>> it out.
>>>
>>> Ben Bolker
>>>
>>>
>>> ########################
>>> ## n<- 100 ## hangs R
>>>
>>> n<- 33
>>>
>>> fn<- paste("tmp",seq(n),"png",sep=".")
>>> for (i in seq(n)) {
>>> png(fn[i])
>>> plot(1:10,1:10,cex="*");
>>> dev.off()
>>> }
>>>
>>> ff<- subset(file.info(fn),select=size)
>>> ff<- ff[!duplicated(ff$size),,drop=FALSE]
>>> table(ff$size)
>>> require(png)
>>> pngs<- lapply(rownames(ff),readPNG)
>>>
>>> png.to.img<- function(x) matrix(rgb(x[,,1],x[,,2],x[,,3]),
>>> nrow=dim(x)[1],ncol=dim(x)[2])
>>>
>>> imgs<- lapply(pngs,png.to.img)
>>>
>>> par(mfrow=c(2,2))
>>> lapply(imgs,function(x) {
>>> plot(0:1,0:1,type="n",ann=FALSE,axes=FALSE)
>>> rasterImage(x,0,0,1,1)
>>> })
>>>
>>> #########################
>>>
>>>> sessionInfo()
>>> R Under development (unstable) (2011-10-06 r57181)
>>> Platform: i686-pc-linux-gnu (32-bit)
>>>
>>> attached base packages:
>>> [1] stats graphics grDevices utils datasets methods base
>>>
>>> other attached packages:
>>> [1] glmmADMB_0.6.5 MASS_7.3-14 png_0.1-3
>>>
>>> loaded via a namespace (and not attached):
>>> [1] grid_2.15.0 lattice_0.19-33 nlme_3.1-102 tools_2.15.0
>>>
>>> ______________________________________________
>>> R-devel@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
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--
Patrick Burns
pbu...@pburns.seanet.com
twitter: @portfolioprobe
http://www.portfolioprobe.com/blog
http://www.burns-stat.com
(home of 'Some hints for the R beginner'
and 'The R Inferno')
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