[R] caret: Errors with createGrid for rf (randomForest)

[David Winsemius]

On Feb 12, 2013, at 10:53 AM, James Jong wrote:

> When I try to crate a grid of parameters for training with caret I get
> various errors:
> ------------------------------------------------------------
>> my_grid <- createGrid("rf")
> Error in if (p <= len) { : argument is of length zero
> 
>> my_grid <- createGrid("rf", 4)
> Error in if (p <= len) { : argument is of length zero
> 
>> my_grid <- createGrid("rf", len=4)
> Error in if (p <= len) { : argument is of length zero
> 
> The documentation for createGrid says:
> ------------------------------------------------------------
> This function creates a data frame that contains a grid of
>     complexity parameters specific methods.
> Usage:
>       createGrid(method, len = 3, data = NULL)
> Arguments:
>  method: a string specifying which classification model to use. See
>          'train' for a full list.
>     len: an integer specifying the number of points on the grid for
>          each tuning parameter.
>    data: the training data (only needed in the case where the 'method'
>          is 'cforest', 'earth', 'bagEarth', 'fda', 'bagFDA', 'rpart',
>          'svmRadial', 'pam', 'lars2', 'rf' or 'pls'). The outcome
>          should be in a column called '.outcome'.

Looking at that example, my first guess would be that your call is missing a proper 'data' argument. It says one is needed if the method is 'rf'.

-- 
david.


> 
> 
> and gives the following examples:
> ------------------------------------------------------------
>     createGrid("rda", 4)
>     createGrid("lm")
>     createGrid("nnet")
> 
>     ## data needed for SVM with RBF:
>     ## Not run:
> 
>     tmp <- iris
>     names(tmp)[5] <- ".outcome"
>     head(tmp)
>     createGrid("svmRadial", data = tmp, len = 4)
>     ## End(Not run)
> 
> 
> What I am doing wrong?
> 
> Also, what is the connection between len  above and tuneLength in the
> argument for train?
> 
> Thanks,
> 
> James
> 
> 	[[alternative HTML version deleted]]
> 
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David Winsemius
Alameda, CA, USA