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

From: Majid Iravani <majid.iravani_at_wsl.ch>
Date: Fri 13 Oct 2006 - 11:33:53 GMT

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 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@wsl.ch

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