[R] Problem with products in R ?

[(Ted Harding)]

Thanks for this link, Gabor (and especially for the link
therein to your posting on Thu May 7 14:10:53 CEST 2009).
This confirms that the R 'bc' package is not on CRAN and
points to where it can be sourced from. I used to have bc.R
installed on an old machine, which has gone into terminal
coma now.

Best wishes,
Ted.


On 04-May-2014 17:10:00 Gabor Grothendieck wrote:
> Checking this with the bc R package (https://code.google.com/p/r-bc/),
> the Ryacas package (CRAN), the gmp package (CRAN) and the Windows 8.1
> calculator all four give the same result:
> 
>> library(bc)
>> bc("168988580159 * 36662978")
> [1] "6195624596620653502"
> 
>> library(Ryacas)
>> yacas("168988580159 * 36662978", retclass = "character")
> 6195624596620653502
> 
>> library(gmp)
>> as.bigz("168988580159") * as.bigz("36662978")
> Big Integer ('bigz') :
> [1] 6195624596620653502
> 
> 
> On Sun, May 4, 2014 at 12:50 PM, Ted Harding <Ted.Harding at wlandres.net>
> wrote:
>> On 04-May-2014 14:13:27 Jorge I Velez wrote:
>>> Try
>>>
>>> options(digits = 22)
>>> 168988580159 * 36662978
>>># [1] 6195624596620653568
>>>
>>> HTH,
>>> Jorge.-
>>
>> Err, not quite ... !
>> I hitch my horses to my plough (with help from R):
>>
>> options(digits=22)
>> 168988580159*8 = 1351908641272 (copy down)
>> 168988580159*7 = 1182920061113  ( " " )
>> 168988580159*9 = 1520897221431  ( " " )
>> 168988580159*2 =  337977160318  ( " " )
>> 168988580159*6 = 1013931480954  ( " " )^3
>> 168988580159*3 =  506965740477  ( " " )
>>
>>          1351908641272
>>         11829200611130
>>        152089722143100
>>        337977160318000
>>      10139314809540000
>>     101393148095400000
>>    1013931480954000000
>>    5069657404770000000
>> ======================
>>    6195624596620653502
>> [after adding up mentally]
>>
>> compared with Jorge's:
>>    6195624596620653568
>>
>> ("02" vs "68" in the final two digits).
>>
>> Alternatively, if using a unixoid system with 'bc' present,
>> one can try interfacing R with 'bc'. 'bc' is an calculating
>> engine which works to arbitrary precision.
>>
>> There certainly used to be a utility in which R can evoke 'bc',
>> into which one can enter a 'bc' command and get the result
>> returned as a string, but I can't seem to find it on CRAN now.
>> In any case, the raw UNIX command line for this calculation
>> with 'bc' (with result) is:
>>
>> $ bc -l
>> [...]
>> 168988580159 * 36662978
>> 6195624596620653502
>> quit
>>
>> which agrees with my horse-drawn working.
>>
>> Best wishes to all,
>> Ted.
>>
>>> On Sun, May 4, 2014 at 10:44 PM, ARTENTOR Diego Tentor <
>>> diegotentor71 at gmail.com> wrote:
>>>
>>>> Trying algorithm for products with large numbers i encountered a
>>>> difference
>>>> between result of 168988580159 * 36662978 in my algorithm and r product.
>>>> The Microsoft calculator confirm my number.
>>>>
>>>> Thanks.
>>>> --
>>>> *        Gráfica ARTENTOR          *
>>>>
>>>> de Diego L. Tentor
>>>> Echagüe 558
>>>> Tel.:0343 4310119
>>>> Paraná - Entre Ríos
>>
>> -------------------------------------------------
>> E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
>> Date: 04-May-2014  Time: 17:50:54
>> This message was sent by XFMail
>>
>> ______________________________________________
>> R-help at r-project.org 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.
> 
> 
> 
> -- 
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com

-------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
Date: 04-May-2014  Time: 18:28:23
This message was sent by XFMail