[R] Calculating Betweenness - Efficiency problem

[jim holtman]

Given that you have the data, exactly what are you expecting the
charts to look like?  You mention vectors, but are you trying to
create a directed graph?  It would be useful to show a small subset of
the data and then how you would expect to process it and what type of
graphs you would like to see.  Factor will basically assign a unique
number associating a value to a character string, and it may have no
relationship to the way you have things stored in your matrix.

A little more information is required so that we understand the
problem you are trying to solve.

On Sat, Jul 19, 2008 at 5:59 PM, Senthil Purushothaman
<spurushothaman at lnxresearch.com> wrote:
> Hi Jim,
>     Thank you for the response. Your suggestion will help me avoid the whole
> text to number conversion process that I perform using LookUp in excel. I
> will definitely give it a shot. But it still doesn't address the vector
> conversion since a graph file is drawn only using the vectors. Assuming that
> I use 'factor' to convert the characters to numbers, how do I convert these
> numbers into vectors?
>
> Thanks,
> Senthil
>
>
>
>
> -----Original Message-----
> From: jim holtman [mailto:jholtman at gmail.com]
> Sent: Sat 7/19/2008 4:49 AM
> To: Senthil Purushothaman
> Cc: r-help at r-project.org
> Subject: Re: [R] Calculating Betweenness - Efficiency problem
>
> It would seem that you can output the initial file from EXCEL, read it
> into R with 'read.csv' and then use 'factor' to convert the characters
> for City1 and City2 to the numbers that you want to use.  Have you
> tried this approach?
>
> On Fri, Jul 18, 2008 at 3:51 PM, Senthil Purushothaman
> <spurushothaman at lnxresearch.com> wrote:
>> Hello,
>>
>> I am calculating 'Betweenness' of a large network using R. Currently, I
>> have the node-node information (City1-City2) in an excel file, present in
>> two columns where column A has City1 and column B has City2 that city1 is
>> connected to. These are the steps that I go through to calculate betweenness
>> of my network.
>>
>> a) Convert the City1-City2 (text) into Number1-Number2 in the excel file
>> where every unique city has a unique number.
>> b) Paste all the city-city information separated by comma into c(...) in
>> the R GUI to obtain the corresponding vectors. As you can imagine this
>> copy-paste operation takes a long time. Example: c(1,3,1,5,2,4,2,5). Just
>> fyi, I have a text file that contains all nodes separated by comma based on
>> the appropriate link information.
>> c) Then, I create a graph file with the above vector.
>> d) I use the graph file to calculate betweenness of my network.
>>
>> I am sure there must be a better, more efficient way to calculate
>> betweenness. Ideally, I would like to just have the City1 - City2 (link)
>> information in two columns in an excel file and calculate the betweenness
>> from that file directly.
>>
>> Please provide an optimal solution for this problem. I appreciate your
>> time and help.
>>
>> Thanks,
>> Senthil
>>
>>        [[alternative HTML version deleted]]
>>
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>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem you are trying to solve?
>
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?