Thanks,

I just remember with RapidMiner, there was always a screen showing the 
effective "weights" assigned to each input variable by the SVM.  These 
numbers themselves weren't good for much, except they really helped to 
visualize the data.  It is rather useful to see how much relative weight 
(significance.) the SVM assigned to each variable.


On 8/31/09 12:54 AM, Achim Zeileis wrote:
> On Mon, 31 Aug 2009, Noah Silverman wrote:
>
>> Steve,
>>
>> That doesn't work.
>>
>> I just trained an SVM with 80 variables.
>> svm_model$coefs gives me  a list of 10,000 items.  My training set is 
>> 30,000 examples of 80 variables, so I have no idea what the 10,000 
>> items represent.
>
> Presumably, the coefficients of the support vectors times the training 
> labels, see help("svm", package = "e1071"). See also
>   http://www.jstatsoft.org/v15/i09/
> for some background information and the different formulations available.
>
>> There should be some attribute that lists the "weights" for each of 
>> the 80 variables.
>
> Not sure what you are looking for. Maybe David, the author auf svm() 
> (and now Cc), can help.
> Z
>
>> -- 
>> Noah
>>
>> On 8/30/09 7:47 PM, Steve Lianoglou wrote:
>>> Hi,
>>>
>>> On Sun, Aug 30, 2009 at 6:10 PM, Noah 
>>> Silverman<noah@smartmediacorp.com> wrote:
>>>
>>>> Hello,
>>>>
>>>> I'm using the svm function from the e1071 package.
>>>>
>>>> It works well and gives me nice results.
>>>>
>>>> I'm very curious to see the actual coefficients calculated for each 
>>>> input
>>>> variable.  (Other packages, like RapidMiner, show you this 
>>>> automatically.)
>>>>
>>>> I've tried looking at attributes for the model and do see a 
>>>> "coefficients"
>>>> item, but printing it returns an NULL result.
>>>>
>>> Hmm .. I don't see a "coefficients" attribute, but rather a "coefs"
>>> attribute, which I guess is what you're looking for (?)
>>>
>>> Run "example(svm)" to its end and type:
>>>
>>> R>  m$coefs
>>>               [,1]
>>>   [1,]  1.00884130
>>>   [2,]  1.27446460
>>>   [3,]  2.00000000
>>>   [4,] -1.00000000
>>>   [5,] -0.35480340
>>>   [6,] -0.74043692
>>>   [7,] -0.87635311
>>>   [8,] -0.04857869
>>>   [9,] -0.03721980
>>> [10,] -0.64696793
>>> [11,] -0.57894605
>>>
>>> HTH,
>>>
>>> -steve
>>>
>>>
>>
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>>

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