使用插入符号时，rf (randomForest) 的 createGrid 错误 [英] Errors with createGrid for rf (randomForest) when using caret

问题描述

当我尝试使用 caret 创建用于训练的参数网格时，我得到各种错误:

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

createGrid 的文档说:

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'.

并给出以下正确工作的例子:

and gives the following examples which work correctly:

 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)

这样，我做错了什么?

len 作为 createGrid 的参数和 train 的参数中的 tuneLength 之间有什么联系?len 和 tuneLength 可以一起使用吗?他们是什么关系?

What is the connection between len as an argument to createGrid and tuneLength in the argument for train? Can len and tuneLength they be used together? What is their relationship?

如果有帮助，这里有一个线程描述如何在 caret 中使用 createGrid 和 train:caret::train:指定模型生成参数

In case it helps, here is a thread describing how to use createGrid with train in caret: caret::train: specify model-generation-parameters

推荐答案

您从示例中提取的代码对我来说很好用(并注意到它修复了您在 Rhelp 上发布时存在的问题):

The code you pulled from the examples works fine for me (and noting that it fixes the problem that existed when you posted on Rhelp):

tmp <- iris
 names(tmp)[5] <- ".outcome"
 head(tmp)
 createGrid("svmRadial", data = tmp, len = 4)
#-------
     .sigma   .C
1 0.7500934 0.25
2 0.7500934 0.50
3 0.7500934 1.00
4 0.7500934 2.00

>  createGrid("rf", data = tmp, len = 4)
randomForest 4.6-7
Type rfNews() to see new features/changes/bug fixes.

Attaching package: ‘randomForest’

The following object(s) are masked from ‘package:Hmisc’:

    combine

note: only 3 unique complexity parameters in default grid. Truncating the grid to 3 .

  .mtry
1     2
2     3
3     4

我再说一遍:还有什么问题?

I say again: What problem remains?

这篇关于使用插入符号时，rf (randomForest) 的 createGrid 错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！