<<insert bug report here>>
When invoking "uniroot" with any argument named "u", uniroot exits
with error: "Error in f(lower, ...) : argument "u" is missing, with no
default". This error occurs whether or not "u" determines the root.
Giving "u" a default value results in garbage from uniroot.
## Define a function with a root:
> test<-function(x,a) (x-a)^3
## Find the root:
> uniroot(test,c(0,1),a=.75)
$root
[1] 0.7500141
$f.root
[1] 2.793453e-15
$iter
[1] 22
$estim.prec
[1] 6.103516e-05
## All is well. Change argument "a" to "u":
> test<-function(x,u) (x-u)^3
## Plot it:
> plot(seq(0,1,by=.1),test(seq(0,1,by=.1),u=.75),type='l')
## All is well. Find the root:
> uniroot(test,c(0,1),u=.75)
Error in f(lower, ...) : argument "u" is missing, with no default
## Define a new function with the same root:
> test<-function(x,a,u) (x-a)^3 /u
## Plot it:
> plot(seq(0,1,by=.1),test(seq(0,1,by=.1),a=.75,u=.2),type='l')
## All is well. Find the root:
> uniroot(test,c(0,1),a=.75,u=.2)
Error in f(lower, ...) : argument "u" is missing, with no default
## Give u a default value:
> test<-function(x,a,u=.2) (x-a)^3 /u
## Find the root:
> uniroot(test,c(0,1),a=.75,u=.2)
Error in uniroot(test, c(0, 1), a = 0.75, u = 0.2) :
f() values at end points not of opposite sign
## Oh, really?
> test(0,.75,.2)
[1] -2.109375
> test(1,.75,.2)
[1] 0.078125
--please do not edit the information below--
Version:
platform = i686-redhat-linux-gnu
arch = i686
os = linux-gnu
system = i686, linux-gnu
status =
major = 2
minor = 2.1
year = 2005
month = 12
day = 20
svn rev = 36812
language = R
Locale:
C
Search Path:
.GlobalEnv, package:methods, package:stats, package:graphics,
package:grDevices, package:utils, package:datasets, Autoloads, package:base
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
