I was off for few days and as nobody seems to answer I will try
again.
It is probably not trivial with matrix (possibly with combination of
outer and some subsequent selection) but if you can transfer it to
data frame (or list) you could use mapply
tj - 1:5
vj - matrix(1:25, 5,5)
mapply(*, data.frame(vj), tj)
anyway it is always advisable to provide some example what you want
to achieve. Usually when I try to elaborate an example I find the
answer myself.
HTH
Petr
On 3 Oct 2006 at 11:50, Dina Said wrote:
Date sent: Tue, 03 Oct 2006 11:50:39 +0200
From: Dina Said [EMAIL PROTECTED]
To: r-help@stat.math.ethz.ch
Subject:Re: [R] Summation in R
Thanks Pikal for your reply
I want element wise summation. If t is a vector of 5, v is a matrix
of 5*5 then I want the answer to be a matrix of 5*5 by
multiplying each element in t (t_j) by each vector in v (v_j).
Dina Petr Pikal wrote:
Hi
you shall probably to be more specific
tj-rnorm(5)
vj-matrix(25,5,5)
sum(tj*vj)
[1] 149.2977
gives you an answer but maybe not the answer you want.
HTH
Petr
On 3 Oct 2006 at 8:58, Dina Said wrote:
Date sent: Tue, 03 Oct 2006 08:58:15 +0200
From: Dina Said [1][EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject:[R] Summation in R
Hello!
Maybe this is a trivial question as I'm still a new baby in R but I
wish that u will help me.
I want to calculate the following
U= sum (t_j*v_j)
where t_j is a vector
and v_j is the matrix
Thanks
Dina
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References
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Petr Pikal
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