[R] Newbie hung up with matrices

rwatkins@cornerstonelp.com rwatkins at cornerstonelp.com
Fri May 16 19:00:42 CEST 2003


Hi all:
	Thanks in advance for your assistance.

	I just started learning R.  I'm trying to use the Help and the downloadable
manuals.  I am stuck on trying to multiply matrices.  Can anyone please
supply a couple of lines of code that I can plug into a fresh console to see
how  a double precision (1x3) matrix is multiplied by a double precision
(3x3) matrix?  I keep getting an error message,"Error in x%*%A: requires
numeric matrix/vector arguments".

	I have some VBA and VB experience (thus a little Object Oriented
programming experience), am I right in beliving that I am not "dimensioning"
correctly?  I have been trying the following example:
		A<-matrix
		A<-read.csv("test33.csv"), where the data is
				A,B,C
				1,4,7
				2,5,8
				3,6,9

		x<-c(4,5,6)
		x%*%A
			ERROR (as shown above)

	ALSO, I have downloaded the RExcel add-in, but have not found any reference
manual, etc that describes how to use it.  Any suggestions here are
appreciated, as I primarily do my work in Excel.

	Are there any good books available that will help me in my quest to become
a more adept user of R?  I know I am going to need this package for
multivariate regressions, etc.

	Again, thanks in advance for your time and consideration.




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