From: Duncan Murdoch <murdoch_at_stats.uwo.ca>

Date: Tue, 05 Feb 2008 22:45:41 -0500

R-help_at_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. Received on Wed 06 Feb 2008 - 03:52:12 GMT

Date: Tue, 05 Feb 2008 22:45:41 -0500

jim holtman wrote:

> Your function 'll' only returns a single value when passed a vector:

*>
**>
**>> x <- seq(0,2,.1)
**>> ll(x)
**>>
**> [1] -7.571559
**>
**>
**> 'plot' expects to pass a vector to the function and have it return a
**> vector of the same length; e.g.,
**>
**>
**>> sin(x)
**>>
**> [1] 0.00000000 0.09983342 0.19866933 0.29552021 0.38941834 0.47942554
**> 0.56464247 0.64421769 0.71735609
**> [10] 0.78332691 0.84147098 0.89120736 0.93203909 0.96355819 0.98544973
**> 0.99749499 0.99957360 0.99166481
**> [19] 0.97384763 0.94630009 0.90929743
**>
**>
**> So you either have to rewrite your function, or have a loop that will
**> evaluate the function at each individual point and then plot it.
**>
*

Or use Vectorize, e.g.

Duncan Murdoch

> On Feb 5, 2008 7:06 PM, John Smith <zmring@gmail.com> wrote:

*>
**>> Dear R-users,
**>>
**>> Suppose I have defined a likelihood function as ll(tau), how can I plot this
**>> likelihood function by calling it by plot?
**>>
**>> I want to do it like this:
**>>
**>> ll <- function(tau)
**>> {
**>> w <- 1 / (s^2 + tau^2)
**>> mu <- sum(theta * w) / sum(w)
**>> -1/2*sum((theta-mu)^2*w -log(w))
**>> }
**>> plot(ll, 0, 2)
**>>
**>>
**>>
**>> But have the following error:
**>> Error in xy.coords(x, y, xlabel, ylabel, log) :
**>> 'x' and 'y' lengths differ
**>> In addition: Warning messages:
**>> 1: In s^2 + tau^2 :
**>> longer object length is not a multiple of shorter object length
**>> 2: In theta * w :
**>> longer object length is not a multiple of shorter object length
**>> 3: In (theta - mu)^2 * w :
**>> longer object length is not a multiple of shorter object length
**>>
**>>
**>> Thanks
**>>
**>> [[alternative HTML version deleted]]
**>>
**>> ______________________________________________
**>> R-help_at_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.
**>>
**>>
**>
**>
**>
**>
*

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