On 28 Oct 2013, at 13:07 , kmmoon100 <k.m...@student.unimelb.edu.au> wrote:
> Hello everyone,
>
> This is Kangmin.
>
> I am trying to produce shape and scale of my wind data. My data is based on
> wind speed frequency with 1km/hr increment. data is described below.
>
> Windspeed (km/h) Frequency
> 1 351
> 2 147
> 3 317
> 4 378
> 5 527
> 6 667
> 7 865
> 8 970
> 9 987
> 10 907
> 11 905
> 12 642
> 13 1000
> 14 983
> 15 847
> 16 842
> 17 757
> 18 698
> 19 632
> 20 626
> 21 599
> 22 529
> 23 325
> 24 391
> 25 356
> 26 267
> 27 230
> 28 223
> 29 190
> 30 142
> 31 124
> 32 104
> 33 97
> 34 37
> 35 62
> 36 46
> 37 42
> 38 24
> 39 9
> 40 13
> 41 9
> 42 5
> 43 2
>
> R codes to calculate shape and scale are described below:
>
> Pine.windfrequency.4weeks<-read.table("C:/Users/kmoon/Documents/Pine_frequency_4weeks.csv",header=TRUE,sep=",")
> fitdistr(Pine.windfrequency.4weeks$Frequency, densfun="weibull")
>
> I have got an error message when I was using 'fitdistr' function
>
> "Error in fitdistr(Pine.windfrequency.4weeks$Frequency, densfun = "weibull")
> :
> optimization failed"
>
> Please help me calculating shape and scale of weibull distribution.
>
> And please understand that I am not an user familiar with R program but I am
> really trying to make my analysis work on R!
There really is no substitute for knowledge and understanding! Did it not occur
to you that the Windspeed column needs to enter into your analysis?
I suppose you wanted the following:
> tt<-read.delim("/tmp/foo")
> summary(tt)
Windspeed..km.h. Frequency
Min. : 1.0 Min. : 2.0
1st Qu.:11.5 1st Qu.: 100.5
Median :22.0 Median : 351.0
Mean :22.0 Mean : 415.7
3rd Qu.:32.5 3rd Qu.: 682.5
Max. :43.0 Max. :1000.0
> x <- rep(tt$Windspeed..km.h., tt$Frequency)
> library(MASS)
> fitdistr(x, densfun="weibull")
shape scale
1.99900495 16.43640142
( 0.01174133) ( 0.06468371)
Warning messages:
1: In densfun(x, parm[1], parm[2], ...) : NaNs produced
2: In densfun(x, parm[1], parm[2], ...) : NaNs produced
3: In densfun(x, parm[1], parm[2], ...) : NaNs produced
4: In densfun(x, parm[1], parm[2], ...)
>
> Thank you!!!
>
> Kangmin.
>
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Optimization-failed-in-fitdistr-Weibull-distribution-tp4679167.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd....@cbs.dk Priv: pda...@gmail.com
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