[R] general inverse solver?

baptiste auguie ba208 at exeter.ac.uk
Wed Feb 11 10:25:56 CET 2009


In a different perspective the sage project might also be an option,  
it seems to interface to Maxima and R among other things. I haven't  
tested it myself though.

http://www.sagemath.org/index.html

Best wishes,

baptiste


PS:  sagemath.org is a well-thought website, perhaps a good  
inspiration for the new design discussed recently?


On 11 Feb 2009, at 07:56, Hans W. Borchers wrote:

> Gabor Grothendieck <ggrothendieck <at> gmail.com> writes:
>
>>
>> I am not sure what the point of all this is.
>
>
> The point of all this is:
>
> 1.  Some users of R here on the list apparently would like to have  
> more powerful
> CAS functionalities than Yacas can provide.
>
> 2. Many of the solution hints to Ryacas on this list were simply not  
> solving the
> resp. problem, so the 80/20 statement of yours may be downright wrong.
>
> 3. Maxima does incorporate a socket server and can be integrated  
> into other
> systems, see EULER (do you never listen?).
>
> What are you mourning about? Of course, it was great that you made  
> available
> Yacas for R. But others have the right to discuss their wishes here  
> w/o being
> 'slammed' every time with questionable hints to Ryacas.
>
> I agree arguments have been exchanged and we should stop here. After  
> this
> discussion, I wish someone would think about an Rmaxima package  
> (along the lines
> of EULER, e.g.), I cant do it, unfortunately.
>
> Hans Werner Borchers
>
>
>> This is an R list, not a CAS list.  The recommendation to use yacas  
>> is based on
>> the fact  that there is an interface between R and yacas.  There is  
>> no
>> interface between
>> R and Maxima so Maxima is not in the running.  Anyone who has used
>> Maxima knows that
>> is an impressive piece of software but that's not the point.
>>
>> Regarding, why there is no interface to Maxima, its because its  
>> harder
>> to interface to
>> Maxima than yacas.   There are two problems here:
>>
>> 1. Maxima does not incorporate a socket server as far as I know.
>> You would have to write it and that may or may not need an in depth
>> understanding of Maxima to do so but in any case represents work.
>> With yacas you don't have to write a server since yacas itself  
>> already
>> contains a server. Just run:
>>  yacas --server .,.
>> and the server side is done. (In the case of yacas it would also be
>> possible to use its C interface for an in-process interface or  
>> presumably
>> the java interface of the new java version of yacas.  With Maxima
>> it would be more problematic since its written in Lisp.)
>>
>> 2. Once you have created some sort of communications channel
>> then what?  If you want more than a crude interface that passes
>> an unprocessed character string to the CAS and then passes one
>> back then you will want to translate between R and the CAS.  With
>> yacas, OpenMath facilitates this greatly.
>>
>> The end result is that its more work to meaningfullly interface with
>> Maxima than with yacas yet yacas satisfies the majority of
>> needs of a CAS.  There is the minority who need more powerful
>> algorithms but I think it was a reasonable step to handle the 80%
>> that can be accommodated most easily first by using yacas. The
>> remaining 20%, which is what the other respondents to this thread
>> are discussing will in part be addressed in the future possibly, in
>> part, by the second project I am working on now.  Perhaps some
>> would quibble with the 80/20 and if you are in the 20 it probably
>> seems like 100 but we will never settle that question definitively.
>>
>
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_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag



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