Re: [R] matrix multiplication question
Hi Murali, So, the solution to your problem will be to explicitly convert your matrix to a numeric matrix. Maybe matrix (?matrix) will do, or you'll also have to use as.numeric (?as.numeric). The strings on the left seem to me to be the row labels, right..?, not elements in the matrix/table. As a newbie, the thing you probably have to get used to/read up with is the distinction between tables, which can contain any sort of data and can not always be used in matrix calculations and (numeric) matrices/vectors. Cheers, Tsjerk On Fri, Jul 18, 2008 at 3:47 AM, Murali K [EMAIL PROTECTED] wrote: Hello, I am a newcomer to R and therefore apologize for posting such a basic question. I am trying to multiply 2 matrices t(X1)%*%X1, where t(X1) is: 1 2 3 4 5 8 12 13 20 24 26 27 31 33 34 36 37 40 41 42 45 46 47 48 49 ones 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Shadow 0 1 1 1 1 1 1 1 0 11 1 1 0 1 0 1 0 1 1 0 1 0 1 0 However, when I try to perform this operation, I obtain: Error in t(X1) %*% X1 : requires numeric matrix/vector arguments Can someone please tell me what I seem to be doing wrong? thanks. Sincerely, Murali Kuchibhotla Murali Kuchibhotla Department of Economics Iowa State University Office:75,Heady Phone:515-294-5452 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- Tsjerk A. Wassenaar, Ph.D. Junior UD (post-doc) Biomolecular NMR, Bijvoet Center Utrecht University Padualaan 8 3584 CH Utrecht The Netherlands P: +31-30-2539931 F: +31-30-2537623 __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] matrix multiplication question
Once you get your matrices in order you do not want to use t(X) %*% X. Instead, use crossprod(X). They do the same thing, but the former is the matrix operations based on the algebraic representation whereas numerical analysts will prefer the methods used in crossprod (hence the reason it exists). -Original Message- From: [EMAIL PROTECTED] on behalf of Duncan Murdoch Sent: Fri 7/18/2008 1:00 AM To: Murali K Cc: r-help@r-project.org Subject: Re: [R] matrix multiplication question On 17/07/2008 9:47 PM, Murali K wrote: Hello, I am a newcomer to R and therefore apologize for posting such a basic question. I am trying to multiply 2 matrices t(X1)%*%X1, where t(X1) is: It's hard to say for sure, but it looks as though X1 really isn't a numeric matrix. The ones and Shadow entries on the left look like character or factor data. To find out what X1 is, you can run str(X1). Duncan Murdoch 1 2 3 4 5 8 12 13 20 24 26 27 31 33 34 36 37 40 41 42 45 46 47 48 49 ones 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Shadow 0 1 1 1 1 1 1 1 0 11 1 1 0 1 0 1 0 1 1 0 1 0 1 0 However, when I try to perform this operation, I obtain: Error in t(X1) %*% X1 : requires numeric matrix/vector arguments Can someone please tell me what I seem to be doing wrong? thanks. Sincerely, Murali Kuchibhotla Murali Kuchibhotla Department of Economics Iowa State University Office:75,Heady Phone:515-294-5452 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] matrix multiplication question
Hello, I am a newcomer to R and therefore apologize for posting such a basic question. I am trying to multiply 2 matrices t(X1)%*%X1, where t(X1) is: 1 2 3 4 5 8 12 13 20 24 26 27 31 33 34 36 37 40 41 42 45 46 47 48 49 ones 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Shadow 0 1 1 1 1 1 1 1 0 11 1 1 0 1 0 1 0 1 1 0 1 0 1 0 However, when I try to perform this operation, I obtain: Error in t(X1) %*% X1 : requires numeric matrix/vector arguments Can someone please tell me what I seem to be doing wrong? thanks. Sincerely, Murali Kuchibhotla Murali Kuchibhotla Department of Economics Iowa State University Office:75,Heady Phone:515-294-5452 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] matrix multiplication question
On 17/07/2008 9:47 PM, Murali K wrote: Hello, I am a newcomer to R and therefore apologize for posting such a basic question. I am trying to multiply 2 matrices t(X1)%*%X1, where t(X1) is: It's hard to say for sure, but it looks as though X1 really isn't a numeric matrix. The ones and Shadow entries on the left look like character or factor data. To find out what X1 is, you can run str(X1). Duncan Murdoch 1 2 3 4 5 8 12 13 20 24 26 27 31 33 34 36 37 40 41 42 45 46 47 48 49 ones 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Shadow 0 1 1 1 1 1 1 1 0 11 1 1 0 1 0 1 0 1 1 0 1 0 1 0 However, when I try to perform this operation, I obtain: Error in t(X1) %*% X1 : requires numeric matrix/vector arguments Can someone please tell me what I seem to be doing wrong? thanks. Sincerely, Murali Kuchibhotla Murali Kuchibhotla Department of Economics Iowa State University Office:75,Heady Phone:515-294-5452 [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
