limits

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limits

Hassan Mohamed
Hey,
what is the R function for the mathematical limit ?
e.g. to calculate  and return the amount that the expression
X^2 +X +2
approach
as X approach 2
(X-> 2)
thanks
hassan


     
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JGR

r@quantide.com
Dear R User
I am using JGR on a Linux Ubuntu Computer with 2 Cpus
When Opening JGR, one Cpu goes up to 100% even if no calculation is yet
started
Did any of you already noticed this strange behaviour?
Thanks for your help
Andrea

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Re: limits

Jorge I Velez
In reply to this post by Hassan Mohamed
Dear Hassam,
Take a look at the section 5.8 in [1].

HTH,

Jorge

[1] http://cran.r-project.org/web/packages/Ryacas/vignettes/Ryacas.pdf


On Tue, May 5, 2009 at 5:39 AM, Hassan Mohamed
<[hidden email]>wrote:

> Hey,
> what is the R function for the mathematical limit ?
> e.g. to calculate  and return the amount that the expression
> X^2 +X +2
> approach
> as X approach 2
> (X-> 2)
> thanks
> hassan
>
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

        [[alternative HTML version deleted]]

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Re: limits

Uwe Ligges-3
In reply to this post by Hassan Mohamed


Hassan Mohamed wrote:
> Hey,
> what is the R function for the mathematical limit ?
> e.g. to calculate  and return the amount that the expression
> X^2 +X +2
> approach
> as X approach 2
> (X-> 2)


So you want some software that can do symbolic calculations? In that
case use other software. R is designed for numerical analyses.

Uwe Ligges


> thanks
> hassan
>
>
>      
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

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Re: JGR

Uwe Ligges-3
In reply to this post by r@quantide.com


[hidden email] wrote:
> Dear R User
> I am using JGR on a Linux Ubuntu Computer with 2 Cpus
> When Opening JGR, one Cpu goes up to 100% even if no calculation is yet
> started
> Did any of you already noticed this strange behaviour?

Does it take very long? On the first start it builds some databases and
that takes some time if you have installed many packages.

Uwe Ligges


> Thanks for your help
> Andrea
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

______________________________________________
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Re: JGR

r@quantide.com
The point is that one Cpu stays at 100% for all time JGR is up.
Any ideas?
Andrea

Uwe Ligges wrote:

>
>
> [hidden email] wrote:
>> Dear R User
>> I am using JGR on a Linux Ubuntu Computer with 2 Cpus
>> When Opening JGR, one Cpu goes up to 100% even if no calculation is
>> yet started
>> Did any of you already noticed this strange behaviour?
>
> Does it take very long? On the first start it builds some databases
> and that takes some time if you have installed many packages.
>
> Uwe Ligges
>
>
>> Thanks for your help
>> Andrea
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>

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Re: JGR

Stefan Grosse-2
On Tue, 05 May 2009 15:12:00 +0200 "[hidden email]" <[hidden email]>
wrote:

RC> The point is that one Cpu stays at 100% for all time JGR is up.
RC> Any ideas?
RC> Andrea

I believe it is a bug with JGR. Unfortunately it is existing for quite
some time now. (I am using Fedora Linux since years and try it from
time to time.)

Just try another gui like emacs with ess or rkward.

hth
Stefan

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Re: limits

Mike Prager
In reply to this post by Uwe Ligges-3
Uwe Ligges <[hidden email]> wrote:

> So you want some software that can do symbolic calculations? In that
> case use other software. R is designed for numerical analyses.

In particular, if you are looking for good free software, you
might try Maxima.


--
Mike Prager, NOAA, Beaufort, NC
* Opinions expressed are personal and not represented otherwise.
* Any use of tradenames does not constitute a NOAA endorsement.

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Re: limits

Gabor Grothendieck
In reply to this post by Hassan Mohamed
Try the rSymPy or Ryacas packages.

In the rSymPy code below the var command defines x
as symbolic to sympy and then we perform the
computation:

> library(rSymPy)
Loading required package: rJava
> sympy("var('x')")
[1] "x"
> sympy("limit(x*x + x + 2, x, 2)")
[1] "8"

Or using devel version define x as symbolic first to sympy
and then to R:

> library(rSymPy)
> source("http://rsympy.googlecode.com/svn/trunk/R/Sym.R")
> sympy("var('x')")
[1] "x"
> x <- Sym("x")
> limit(x*x + x + 2, x, 2)
[1] "8"

or using Ryacas:

> library(Ryacas)
Loading required package: XML
> x <- Sym("x")
> Limit(x^2+x+2, x, 2)
[1] "Starting Yacas!"
expression(8)

More info is available here which you should read before
using these packages:

http://rsympy.googlecode.com
http://ryacas.googlecode.com


On Tue, May 5, 2009 at 5:39 AM, Hassan Mohamed
<[hidden email]> wrote:

> Hey,
> what is the R function for the mathematical limit ?
> e.g. to calculate  and return the amount that the expression
> X^2 +X +2
> approach
> as X approach 2
> (X-> 2)
> thanks
> hassan
>
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.