Message-ID: <52331AC8.3060601@tu-dresden.de>
Date: 2013-09-13T14:01:44Z
From: Thomas Petzoldt
Subject: numerical issue in contour.default?
Dear R developers,
I found a small issue while plotting contours of data containing both
"usual" and "very small" numbers. It appeared with both R 3.0.1 and
R-Devel on Windows, and I could reproduce it on Linux. Would it be
possible to solve this before the upcoming release?
Thanks a lot for developing this great software!
Thomas
Example:
########
set.seed(357)
z1 <- matrix(runif(100, -1e-180, 1e-180), nrow = 10)
contour(z1) # ok
z2 <- matrix(c(runif(50, -1, 1), runif(50, -1e-180, 1e-180)), nrow = 10)
contour(z2) # Error in contour.default(z) : k != 2 or 4
contour(z2 * 1e20) # 20 worked, 19 produced error
contour(round(z2, 179)) # rounding to 179 digits works but not 180
> sessionInfo()
R Under development (unstable) (2013-09-11 r63910)
Platform: x86_64-w64-mingw32/x64 (64-bit)
locale:
[1] LC_COLLATE=German_Germany.1252 LC_CTYPE=German_Germany.1252
[3] LC_MONETARY=German_Germany.1252 LC_NUMERIC=C
[5] LC_TIME=German_Germany.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
--
Dr. Thomas Petzoldt
Technische Universitaet Dresden
Faculty of Environmental Sciences
Institute of Hydrobiology
01062 Dresden, Germany
E-Mail: thomas.petzoldt at tu-dresden.de
http://tu-dresden.de/Members/thomas.petzoldt