[R] multiply two matrixes with the different dimension column by column

[Majid Iravani]

Dear all,
I would like to multiply two matrixes with the different dimension column 
by column. Let make an example:
If I have two matrixes "X" and "Y"as follow:

X<- matrix(1:12, nrow=4, ncol=3, dimnames=list(c("A","B","C","D"), 
c("stage1","stage2","stage3")))
Y<- matrix(1:28, nrow=4, ncol=7, dimnames=list(c("A","B","C","D"), 
c("site1","site2","site3","site4","site5", "site6","site7")))

  I would like to multiply first column of the "Y"matrix (site1) to the all 
of the columns in "X"matrix. Then, the product will be three new columns 
(for example:site1stage1, site1stage2 and site1stage3 or something like 
this) which I want to add to "Y"matrix. As my site (Y) dataset has too many 
columns, it's not easy to do it in Excel and I'm looking for a command in R 
to prepare a new data frame for more analysis. So I would greatly 
appreciate if anybody can help me in this case.
Thanks in advance
Majid
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  Majid Iravani
  PhD Student
  Swiss Federal Research Institute WSL
  Research Group of Vegetation Ecology
  Zürcherstrasse 111  CH-8903 Birmensdorf  Switzerland
  Phone: +41-1-739-2693
  Fax: +41-1-739-2215
  Email: Majid.iravani at wsl.ch
http://www.wsl.ch/staff/majid.iravani/