[R] Uninformative error msgs w/ svm.default - Error in svm.default ... y must be a vector or a factor -

[Ken Termiso]

Hello,
 
I'm using recursive SVM script (rSVM - http://www.stanford.edu/group/wonglab/RSVMpage/R-SVM.html ) on some microarray data. The data to be input are log2, as numeric matrix w/ attributes -- 
 
str(svm_num_mat)
 num [1:10, 1:12340] 13.1 13.1 13.1 13.1 13.0 ...
 - attr(*, "dimnames")=List of 2
  ..$ : chr [1:10] "rma_log2_con_sample_1" "rma_log2_con_sample_2" "rma_log2_con_sample_3" "rma_log2_con_sample_4" ...
  ..$ : chr [1:12340] "AFFX-HSAC07/X00351_3_at" "AFFX-HSAC07/X00351_5_at" "AFFX-HSAC07/X00351_M_at" "AFFX-HUMGAPDH/M33197_3_at" ...
 
and the class labels --
> str(m.cl.f)
 Factor w/ 2 levels "-1","1": 2 2 2 2 2 1 1 1 1 1
> 
> m.cl.f
 [1] 1  1  1  1  1  -1 -1 -1 -1 -1
Levels: -1 1
 
> mode(m.cl.f)
[1] "numeric"
 
 
the rSVM function is called as such (it is a wrapper for svm in e1071, which then calls low-level svm.default ) -
> rsvm_output <- RSVM(x=svm_num_mat, y=m.cl.f, ladder=laddy, CVtype="LOO" )
Error in svm.default(xTrain[, SelInd], yTrain, scale = F, type = "C-classification",  : 
  y must be a vector or a factor.
 
 
....the 'laddy' variable just specifies a recursive parameter for the overlying rSVM procedure - here, it calls the 1st round w/ all 12340 elements, then with the highest scoring 9255 elements, etc.. 
 
> laddy
 [1] 12340  9255  6941  5206  3904  2928  2196  1647  1235   926   694   520
[13]   390   292   219   164   123    92    69    52    39    29    22    16
[25]    12     9     7     5
 
 
...however, the error depends on the matrix size --
> rsvm_output <- RSVM(x=svm_num_mat[,5000:6000], y=m.cl.f, ladder=laddy[laddy gc()
         used (Mb) gc trigger (Mb) max used (Mb)
Ncells 185948 10.0     467875 25.0   467875 25.0
Vcells 758060  5.8    2983420 22.8  2798915 21.4
>
 
 
 
..help?
 
Thanks,
-Ken

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