[R] Multiplying each row of a big matrix with a vector

Bill.Venables at csiro.au Bill.Venables at csiro.au
Wed Jan 30 08:52:56 CET 2008

port <- as.vector(ret %*% port)

should do it. 

Bill Venables

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Megh Dal
Sent: Wednesday, 30 January 2008 5:20 PM
To: r-help at stat.math.ethz.ch
Subject: [R] Multiplying each row of a big matrix with a vector

I have a big matrix 'ret'. I want to multiply each row of it with a 2nd
vector 'pos', resulting result, I want to save in a vector named 'port'.
I wrote following code:
  > pos
[1]  2593419  2130220  6198197  1673888  1980000  1784732  2052120
-7490228 -5275000

  > dim(ret)
[1] 500   9

  > fu    # user defined function
    fu = x %*% t(pos)
port = apply(ret, 1, fu)

  > dim(port)
[1]  81 500

  My desire is to get port as a vector with length 500. However I am not
getting that?
  Can anyone tell me how to correct that? 


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