[R] apply lm() for all the columns of a matrix

[Dimitris Rizopoulos]

Well, could you provide a little bit more information regarding what 
you are trying to do (e.g., reproducible example).

Best,
Dimitris

----
Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Costas Douvis" <cdouvis at geol.uoa.gr>
To: <r-help at r-project.org>; "Mark Leeds" <markleeds at verizon.net>; 
"Dimitris Rizopoulos" <dimitris.rizopoulos at med.kuleuven.be>
Cc: "Chuck Cleland" <ccleland at optonline.net>
Sent: Wednesday, April 09, 2008 3:44 PM
Subject: Re: [R] apply lm() for all the columns of a matrix


> Thank you all very much for replying. Of course you are absolutely 
> right
> but unfortunately I really deal with the case of a 4-d matrix so 
> what you
> said does not apply. I should have specified but being a new R user 
> I
> hadn't realized the difference between a matrix and an array.
>
> So please tell me if you know a fast way (not using a loop) to 
> perform a
> linear fit on all the vectors of the 4-th dimension of a 4-d array.
>
> Thanks again
> Kostas
>
>> If you have the same design matrix then you can specify a matrix of
>> responses in lm(), e.g.,
>>
>> Y <- matrix(rnorm(100*10), 100, 10)
>> x <- rnorm(100)
>>
>> fit <- lm(Y ~ x)
>> fit
>> summary(fit)
>>
>>
>> I hope it helps.
>>
>> Best,
>> Dimitris
>>
>> ----
>> Dimitris Rizopoulos
>> Biostatistical Centre
>> School of Public Health
>> Catholic University of Leuven
>>
>> Address: Kapucijnenvoer 35, Leuven, Belgium
>> Tel: +32/(0)16/336899
>> Fax: +32/(0)16/337015
>> Web: http://med.kuleuven.be/biostat/
>>      http://www.student.kuleuven.be/~m0390867/dimitris.htm
>>
>>
>> ----- Original Message -----
>> From: "Costas Douvis" <cdouvis at geol.uoa.gr>
>> To: <r-help at r-project.org>
>> Sent: Wednesday, April 09, 2008 12:55 PM
>> Subject: [R] apply lm() for all the columns of a matrix
>>
>>
>>> Hi all,
>>>
>>> My question is not really urgent. I can write a loop and solve the
>>> problem. But I know that I'll be in a similar situation many more
>>> times so
>>> it would be useful to find out the answer
>>>
>>> Is there a fast way to perform linear fit to all the columns of a
>>> matrix?
>>> (or in the one dimension of a multi-dimensional array.) I'm 
>>> talking
>>> about
>>> many single linear fits, not about a multiple fit. I thought that 
>>> a
>>> combination of apply and lm would do it but I can't make it work
>>>
>>> Thank you
>>> Kostas
>>>
>>>
>>> --
>>> Kostas Douvis
>>> PhD Student
>>> University of Athens - Department of Geography and Climatology
>>> Academy of Athens - Research Centre for Atmospheric Physics and
>>> Climatology
>>> email: cdouvis at geol.uoa.gr
>>> tel: +30-210-8832048
>>>
>>> ______________________________________________
>>> 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.
>>>
>>
>>
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>>
>>
>
> 


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