Ubuntu and R

You could try the stable/sarge backport from Cran. That's less likely 
to cause problems than using the Etch version, but I'm not using Ubuntu 
so I can't confirm this. Add the following to your sources.list and see 
how it goes:

    deb http://cran.R-project.org/bin/linux/debian stable/

 

I did this in my Ubuntu 5.10 and it works very well...

Fernando Mayer.

Tyler Smith escreveu:

You could try the stable/sarge backport from Cran. That's less likely 
to cause problems than using the Etch version, but I'm not using 
Ubuntu so I can't confirm this. Add the following to your sources.list 
and see how it goes:

    deb http://cran.R-project.org/bin/linux/debian stable/

 

x<-rep(0.02,10)
var(x)
0

1.337451e-35

Hi All,

An annoying but not critical problem I am having is that the variance of
a vector of constants is reported as > 0. I imagine there is a simple
workaround for the following but could not find it after having spent an
embarrassing amount of time.

In Splus:

x<-rep(0.02,10)
var(x)
0

In R:

x<-rep(0.02,10)
var(x)
1.337451e-35

I assumed the problem had to do with machine precision and suitably
modified .Machine$double.eps and .Machine$double.neg.eps which I thought
would fix the problem but without success. Any pointers to a solution
would be appreciated!

Cheers,
Barry Zajdlik

Hi All,

An annoying but not critical problem I am having is that the variance of
a vector of constants is reported as > 0. I imagine there is a simple
workaround for the following but could not find it after having spent an
embarrassing amount of time.

In Splus:

x<-rep(0.02,10)
var(x)
0

In R:

x<-rep(0.02,10)
var(x)
1.337451e-35

I assumed the problem had to do with machine precision and suitably
modified .Machine$double.eps and .Machine$double.neg.eps which I thought
would fix the problem but without success. Any pointers to a solution
would be appreciated!

Cheers,
Barry Zajdlik

Barry Zajdlik wrote:

Hi All,

An annoying but not critical problem I am having is that the variance of
a vector of constants is reported as > 0. I imagine there is a simple
workaround for the following but could not find it after having spent an
embarrassing amount of time.

In Splus:

x<-rep(0.02,10)
var(x)
0

In R:

x<-rep(0.02,10)
var(x)
1.337451e-35

Which version of R and which OS is this? I get 0 for both Linux and
Windows with R-2.2.1.
Anyway, 0.02 is not well representable and hence can be very well the
cause for such a numerical inaccuracy.

I assumed the problem had to do with machine precision and suitably
modified .Machine$double.eps and .Machine$double.neg.eps which I thought
would fix the problem but without success. Any pointers to a solution
would be appreciated!

Changing .Machine$double.eps does not help to calculate more accurate ...

Uwe Ligges

Cheers,
Barry Zajdlik

Barry Zajdlik wrote:

Hi All,

An annoying but not critical problem I am having is that the variance 
of
a vector of constants is reported as > 0. I imagine there is a simple
workaround for the following but could not find it after having spent 
an
embarrassing amount of time.

In Splus:

x<-rep(0.02,10)
var(x)
0

In R:

x<-rep(0.02,10)
var(x)
1.337451e-35

Which version of R and which OS is this? I get 0 for both Linux and
Windows with R-2.2.1.
Anyway, 0.02 is not well representable and hence can be very well the
cause for such a numerical inaccuracy.

I assumed the problem had to do with machine precision and suitably
modified .Machine$double.eps and .Machine$double.neg.eps which I 
thought
would fix the problem but without success. Any pointers to a solution
would be appreciated!

Changing .Machine$double.eps does not help to calculate more accurate 
...

Uwe Ligges

Cheers,
Barry Zajdlik

var(x)

 sessionInfo()

x<-rep(0.02,10)
var(x)

sessionInfo()

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)

var(x)

[1] 1.337451e-35

sessionInfo()

R version 2.1.0, 2005-04-18, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"     



I then decided to download the latest version today but obtained the
same result.

x<-rep(0.02,10)
var(x)

[1] 1.337451e-35

sessionInfo()

R version 2.2.1, 2005-12-20, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"    


I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Again, any thoughts would be appreciated.

Regards,
Barry Zajdlik

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)

var(x)

[1] 1.337451e-35

I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)

var(x)

[1] 1.337451e-35

 sessionInfo()

R version 2.1.0, 2005-04-18, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"     


I then decided to download the latest version today but obtained the
same result.

x<-rep(0.02,10)
var(x)

[1] 1.337451e-35

sessionInfo()

R version 2.2.1, 2005-12-20, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"    


I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Again, any thoughts would be appreciated.

Regards,
Barry Zajdlik

On 2/17/2006 1:17 PM, Barry Zajdlik wrote:

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)

var(x)

[1] 1.337451e-35

sessionInfo()

R version 2.1.0, 2005-04-18, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"     


I then decided to download the latest version today but obtained the
same result.

x<-rep(0.02,10)
var(x)

[1] 1.337451e-35

My guess is that you've got a video driver or some other software that's 
messing with your floating point processor, reducing the precision from 
64 bit to 53 or less.  I can reproduce the error after running 
RSiteSearch, which messes with my fpu in that way:

 > var(rep(0.2, 100))

[1] 0

 > RSiteSearch('fpu')

A search query has been submitted to http://search.r-project.org
The results page should open in your browser shortly

 > var(rep(0.2, 100))

[1] 1.525181e-31

(I'm not blaming RSiteSearch for doing something bad, it's the system 
DLLs that it calls that are at fault.)

I think this is something we should address, but it's not easy.

Duncan Murdoch

sessionInfo()

R version 2.2.1, 2005-12-20, i386-pc-mingw32 

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets" 
[7] "base"    


I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Again, any thoughts would be appreciated.

Regards,
Barry Zajdlik

	  I got the same thing as Duncan:

var(rep(0.2, 100))

[1] 0

RSiteSearch('fpu')

A search query has been submitted to http://search.r-project.org
The results page should open in your browser shortly

var(rep(0.2, 100))

[1] 1.525181e-31

sessionInfo()

R version 2.2.1, 2005-12-20, i386-pc-mingw32

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"     "datasets"
[7] "base"

	  spencer graves

Duncan Murdoch wrote:

On 2/17/2006 1:17 PM, Barry Zajdlik wrote:

Hello all,

Thanks for the responses but I am still annoyed by this seemingly simple
problem; I recorded sessionInfo() as below.

x<-rep(0.02,10)

var(x)

[1] 1.337451e-35

sessionInfo()

R version 2.1.0, 2005-04-18, i386-pc-mingw32

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets"
[7] "base"


I then decided to download the latest version today but obtained the
same result.

x<-rep(0.02,10)
var(x)

[1] 1.337451e-35

My guess is that you've got a video driver or some other software that's
messing with your floating point processor, reducing the precision from
64 bit to 53 or less.  I can reproduce the error after running
RSiteSearch, which messes with my fpu in that way:

var(rep(0.2, 100))

[1] 0

RSiteSearch('fpu')

A search query has been submitted to http://search.r-project.org
The results page should open in your browser shortly

var(rep(0.2, 100))

[1] 1.525181e-31

(I'm not blaming RSiteSearch for doing something bad, it's the system
DLLs that it calls that are at fault.)

I think this is something we should address, but it's not easy.

Duncan Murdoch

sessionInfo()

R version 2.2.1, 2005-12-20, i386-pc-mingw32

attached base packages:
[1] "methods"   "stats"     "graphics"  "grDevices" "utils"
"datasets"
[7] "base"


I Changed .Machine$double.eps to make the calculations LESS accurate.
My thought was that if I reduced the precision, 1-eps would return 1
instead of some number less than 1.  My thought was that if eps were
sufficiently large my sample problem would return a zero.  This didn't
happen though.

Again, any thoughts would be appreciated.

Regards,
Barry Zajdlik