[R] Query regarding linking R with Matlab

[Henrik Bengtsson]

[Forwarding to r-help for completeness. /Henrik]

---------- Forwarded message ----------
From: Henrik Bengtsson <hb at stat.berkeley.edu>
Date: Dec 28, 2006 9:45 PM
Subject: Re: [R] Query regarding linking R with Matlab
To: kalyansikha at yahoo.com


Hi.

On 12/28/06, Bhanu Kalyan.K <kalyansikha at yahoo.com> wrote:
> Respected Sir,
> I am sorry that i forgot to 'setVerbose'. Now when that is set, The result
> is:
>
> > Matlab$startServer(minimize=FALSE)
> [1] 0
>
> > matlab <- Matlab(host="localhost")
>
> > open(matlab)
> [1] TRUE
>
> > setVerbose(matlab, -2)
>
> > res <- evaluate(matlab, "A=1+2;", "B=ones(2,20);")
>
> Sending expression on the Matlab server to be evaluated...: 'A=1+2;
> B=ones(2,20);'
> Received an 'OK' reply (0) from the Matlab server.
> Evaluated expression on the Matlab server with return code 0.
>
> > res
> NULL
>
> > close(matlab)
> Closing connection to host 'localhost' (port 9999)...
>  Received an 'OK' reply (0) from the Matlab server.
> Closing connection to host 'localhost' (port 9999)...done
>
> What should "res" object contain finally when we are doing
> res <- evaluate(matlab, "A=1+2;", "B=ones(2,20);") ??

The return value of evaluate() is NULL when successful (I noticed the
help is saying '0'; I've corrected that for the next version).
Anyway, 'res' contains nothing of interest.  If there is any error on
the Matlab side, an error is thrown in R giving you the details.

What you might want to do is:

data <- getVariable(matlab, "A")
str(data)

>
> once i do
> close(matlab), the matlab server is shutdown,

Yes, the server script is shut down, but Matlab is left running on
purpose so you have a chance to continue working with the Matlab
session by hand.

> However, when i ask for the
> values of A & B in matlab window, the output is displayed correctly. The
> matlab window outputs thus:
> » A
>
> A =
>
>      3
>
> » B
>
> B =
>
>   Columns 1 through 17
>
>      1     1     1     1     1     1     1     1     1     1     1     1
> 1     1     1     1     1
>      1     1     1     1     1     1     1     1     1     1     1     1
> 1     1     1     1     1
>
>   Columns 18 through 20
>
>      1     1     1
>      1     1     1
>
> What do you interpret?

That everything is now working as expected.  See the example of
help(Matlab) to get more ideas how to interact with Matlab from R.

Cheers

Henrik

> Kindly let me know
>
>
> Regards
> Bhanu Kalyan K
>
>
> Bhanu Kalyan K
> BTech CSE Final Year
> reach4kalyan at gmail.com
> Tel :+91-9885238228
>
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