[R] Error in calcCurveGrob(x, x$debug) : End points must not be identical

[Bryan Hanson]

Thanks Paul... I wasn't sure in what way the end points were identical and
was testing differently, and failing to catch it.  I'll have to check my
computations now to see why I'm getting curves that meet this condition, as
I don't think I should be.  But I'm back on track now.  The problem with the
viewport being wrong was limited to the toy example I made.

I'll send you a graphic directly so you can see what I'm working on.

Thanks again for the correct "test" for identical endpoints.  Should have
been able to see that one myself!

Bryan
*************
Bryan Hanson
Professor of Chemistry & Biochemistry
DePauw University, Greencastle IN USA



On 12/5/10 5:17 PM, "Paul Murrell" <paul at stat.auckland.ac.nz> wrote:

> Hi
> 
> Bryan Hanson wrote:
>> Hi All... I haven¹t found mention of this error anywhere.  I'm trying to
>> draw spline curves using grid graphics.  Most of the time, I have no
>> problems, but I have some data sets that give the error in the subject line.
>> I'm not sure which end points are identical, but the end points passed to
>> the function are definitely not identical.
> 
> I get ...
> 
>   which(tst$x.st == tst$x.end & tst$y.st == tst$y.end)
> [1] 11 14
> 
> Also, the viewport you have set up will not show any of the curves
> because its "native" scale is 0 to 1.  The following at least makes the
> curves visible ...
> 
> grid.newpage()
> vp <- viewport(width = 0.9, height = 0.9, x = 0.5, y = 0.5,
>                 xscale=c(-10, 10), yscale=c(-15, 15))
> pushViewport(vp)
> grid.rect(gp = gpar(lty = "dashed", col = "gray"))
> grid.points(0.5, 0.5, pch = 20, gp = gpar(cex = 0.5))
> subset <- -c(11, 14)
> grid.curve(tst$x.st[subset], tst$y.st[subset],
>             tst$x.end[subset], tst$y.end[subset],
>             default.units = "native")
> 
> Paul
> 
> p.s.  Intrigued to know what sort of image you are producing, if you are
> able to share.
> 
>> 
>> Any assistance appreciated!  Bryan
>> 
>> tst <-
>> structure(list(x.st = c(-1, -2, -3, -1, -1.5, -3, -1.5, -1.5,
>> -8, -1, -1.5, -1, -1.5, -2, -1.5, -2, -1, -1.5, -2), y.st =
>> c(1.73205080756888,
>> 3.46410161513776, 5.19615242270663, 1.73205080756888, 2.59807621135332,
>> 5.19615242270663, 2.59807621135332, 2.59807621135332, 13.8564064605510,
>> 1.73205080756888, 2.59807621135332, 1.73205080756888, 2.59807621135332,
>> 3.46410161513776, 2.59807621135332, 3.46410161513776, 1.73205080756888,
>> 2.59807621135332, 3.46410161513776), x.end = c(-6.5, -6.5, -6.5,
>> -4, -4, -4, -1.5, -1, -1, -1.5, -1.5, -2, -2, -2, -3, -3, -8,
>> -8, -8), y.end = c(-11.2583302491977, -11.2583302491977, -11.2583302491977,
>> -6.92820323027551, -6.92820323027551, -6.92820323027551, -2.59807621135332,
>> 1.73205080756888, 1.73205080756888, 2.59807621135332, 2.59807621135332,
>> 3.46410161513776, 3.46410161513776, 3.46410161513776, 5.19615242270663,
>> 5.19615242270663, 13.8564064605510, 13.8564064605510, 13.8564064605510
>> ), grp = c(3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
>> 3, 3), lwd = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1,
>> 2, 5, 2)), .Names = c("x.st", "y.st", "x.end", "y.end", "grp",
>> "lwd"), row.names = 34:52, class = "data.frame")
>> 
>> grid.newpage()
>> vp <- viewport(width = 0.9, height = 0.9, x = 0.5, y = 0.5)
>> pushViewport(vp)
>> grid.rect(gp = gpar(lty = "dashed", col = "gray"))
>> grid.points(0.5, 0.5, pch = 20, gp = gpar(cex = 0.5))
>> grid.curve(tst$x.st, tst$y.st, tst$x.end, tst$y.end,
>>     default.units = "native")
>> 
>> #######
>>> sessionInfo()
>> R version 2.12.0 (2010-10-15)
>> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>> 
>> locale:
>> [1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8
>> 
>> attached base packages:
>> [1] datasets  tools     grid      grDevices graphics  utils
>> [7] stats     methods   base
>> 
>> other attached packages:
>>  [1] gridExtra_0.7      GGally_0.2.2       xtable_1.5-6
>>  [4] mvbutils_2.5.1     ggplot2_0.8.8      proto_0.3-8
>>  [7] reshape_0.8.3      ChemoSpec_1.46     seriation_1.0-2
>> [10] colorspace_1.0-1   TSP_1.0-1          R.utils_1.5.3
>> [13] R.oo_1.7.4         R.methodsS3_1.2.1  rgl_0.92.794
>> [16] lattice_0.19-13    mvoutlier_1.4      plyr_1.2.1
>> [19] RColorBrewer_1.0-2 chemometrics_1.0   som_0.3-5
>> [22] robustbase_0.5-0-1 rpart_3.1-46       pls_2.1-0
>> [25] pcaPP_1.8-3        mvtnorm_0.9-92     nnet_7.3-1
>> [28] mclust_3.4.6       MASS_7.3-8         lars_0.9-7
>> [31] gclus_1.3          cluster_1.13.1     e1071_1.5-24
>> [34] class_7.3-2
>> 
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