Hi, All: Thanks. Here is the code
n = 30 lamdaa = 4 lamdab = 1.5 pa = lamdaa/n pb = lamdab/n x <- seq(0, n/2, len = n/2+1) y <- seq(0, n/2, len = n/2+1) f = factorial(n)/ (factorial(x) * factorial(y) * factorial (n-x-y))* pa^x * pb^y * ((1-pa-pb)^(n-x-y)) wireframe(f ~ x * y, shade = TRUE) The above cannot show anything. Just le t you know that now I changed to cloud, it can display something :) cloud(f ~ x * y, shade = TRUE) I have questions: 1. what does x*y mean here? I don't think it is a vector dot multiplication. I guess it will creat all rows of x and y for all possible combinations? Why wireframe cannot show here? 2. How to show the value on the cloud plot? I have no idea of how much the data value is from the plot. 3. Where can I get resources of R? The help file seems not very helpful to me. For example, the lm () function, its weighted least square option does not say clearly the weight = standard deviation. It said it is to minimize sum w*error^2, which mislead us to think it takes variance. I have to ask experienced people. And everytime the answer depends on luck. Thanks, ----- Original Message ----- From: "Andrew Ward" <[EMAIL PROTECTED]> To: "Sun" <[EMAIL PROTECTED]> Sent: Saturday, October 16, 2004 10:15 PM Subject: RE: [R] how to draw a multivariate function > Dear Sun, > > Could you please provide an example that can be run > by readers of the list? What you've given is > missing at least n and pa. > > Regards, > > Andrew C. Ward, [EMAIL PROTECTED] > Senior Analyst (Quantitative), Tel: +61 7 3864 0439 > Queensland Studies Authority, Fax: +61 7 3229 3318 > 295 Ann Street, > Brisbane Qld 4000, Australia > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Sun > Sent: Sunday, 17 October 2004 12:59 PM > To: R-help mailing list > Subject: [R] how to draw a multivariate function > > > Hi, Rusers: > > Thanks for answering my last questions. I am frustrated in plotting a trinomial pmf function > > f(x,y | n, pa, pb) = factorial(n)/ (factorial(x) * factorial(y) * factorial (n-x-y))* pa^x * pb^y * ((1-pa-pb)^(n-x-y)) > > obviously it is a bivariate function of x and y. But I have put a lot of time on this. > > ********************************** > x <- seq(0, n, len = n/2+1) # for now I set it to n/2 to control x+y <= n > y <- seq(0, n, len = n/2+1) > f = factorial(n)/ (factorial(x) * factorial(y) * factorial (n-x-y))* pa^x * pb^y * ((1-pa-pb)^(n-x-y)) > wireframe(f ~ x * y, shade = TRUE) > ********************************** > > well, but it plots nothing out. > > I wonder if you could help me? Seems R is hard to learn without your help. > > Many thanks, > > Sun > [[alternative HTML version deleted]] > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > This email (including any attached files) is for the intended > recipient(s) only. If you received this email by mistake, please, > as a courtesy, tell the sender, then delete this email. > > The views and opinions are the originator's and do not necessarily > reflect those of the Queensland Studies Authority. All reasonable > precautions have been taken to ensure that this email contained no > viruses at the time it was sent. > > > ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
