R help - Jun 2006 - Adding elements of matrices of different dimensions

If I have two matrices:
> a<-matrix(1:5,ncol=1)
     [,1]
[1,]    1
[2,]    2
[3,]    3
[4,]    4
[5,]    5
> b<-matrix(1:50,ncol=10)
     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,]    1    6   11   16   21   26   31   36   41    46
[2,]    2    7   12   17   22   27   32   37   42    47
[3,]    3    8   13   18   23   28   33   38   43    48
[4,]    4    9   14   19   24   29   34   39   44    49
[5,]    5   10   15   20   25   30   35   40   45    50

How can I add a[1,1] to each column in the first row of b.
and the then add a[2,1] to each column in second row of b
and so on.

I know there must be a way to use the apply function or nested for loops but
I can't seem to get it working in R.
thanks,
michael

	[[alternative HTML version deleted]]

try the following:

matrix(1:50, ncol = 10) + 1:5
# or
b + drop(a)


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
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: "michael papenfus" <papenfus at gmail.com>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, June 27, 2006 7:28 AM
Subject: [R] Adding elements of matrices of different dimensions

> If I have two matrices:
>
>> a<-matrix(1:5,ncol=1)
>
>     [,1]
> [1,]    1
> [2,]    2
> [3,]    3
> [4,]    4
> [5,]    5
>> b<-matrix(1:50,ncol=10)
>
>     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> [1,]    1    6   11   16   21   26   31   36   41    46
> [2,]    2    7   12   17   22   27   32   37   42    47
> [3,]    3    8   13   18   23   28   33   38   43    48
> [4,]    4    9   14   19   24   29   34   39   44    49
> [5,]    5   10   15   20   25   30   35   40   45    50
>
> How can I add a[1,1] to each column in the first row of b.
> and the then add a[2,1] to each column in second row of b
> and so on.
>
> I know there must be a way to use the apply function or nested for 
> loops but
> I can't seem to get it working in R.
> thanks,
> michael
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm