[R] named list 'start' in fitdistr

Ruud H. Koning info at rhkoning.com
Fri Jul 25 17:09:30 CEST 2003

 x <- exp(rnorm(100))
> fitdistr(x,"lognormal",start=list(meanlog=0,sdlog=1))
     meanlog        sdlog   
  -0.09974374    0.92352880 
 ( 0.09235288) ( 0.06530569)


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On 7/25/2003 at 4:50  vincent.stoliaroff at sgcib.com wrote:

>Hi R lovers!
>I'd like to know how to use the parameter 'start' in the function
>obviously I have to provide the initial value of the parameter to optimize
>except in the case of a certain set of given distribution
>Indeed according to the help file for fitdistr
>"     For the following named distributions, reasonable starting values
>     will be computed if `start' is omitted or only partially
>     specified: `cauchy', `gamma', `logistic', `negative binomial' (R
>     only, parametrized by `mu' and `size'), `t', `uniform', `weibull'.
>However I cannot fit an univariate distribution named 'test'
>I get this:
>Error in fitdistr(test, "lognormal") : `start' must be a named list
>> fitdistr(test,"lognormal",start$meanlog=0,start$sdlog=1)
>Error: syntax error
>How I am supposed to type a value for start depending on the distribution
>on which I am fitting my set
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