how do i convert a train data and train label matrices in matlab to libsvm 'train' file format?? i know how to interface libsvm with matlab. But i want to work in libsvm in cmd only. i get this error, i am clueless as why i get this error?

matlab>> libsvmwrite('hamm15x7.train',trainlabel,traindata)
ERROR : can't open output file hamm15x7.train

[md.]

It depends on your data format. A simple way is to use libsvmwrite in the libsvm matlab/octave interface. Take a CSV (comma-separated values) file in UCI machine learning repository as an example. We download SPECTF.train. Labels are in the first column. The following steps produce a file in the libsvm format.

matlab> SPECTF = csvread('SPECTF.train'); % read a csv file

matlab> labels = SPECTF(:, 1); % labels from the 1st column

matlab> features = SPECTF(:, 2:end);

matlab> features_sparse = sparse(features); % features must be in a sparse matrix

matlab> libsvmwrite('SPECTFlibsvm.train', labels, features_sparse);

The tranformed data are stored in SPECTFlibsvm.train.

Alternatively, you can use convert.c to convert CSV format to libsvm format.

Answer 1

[Walter Roberson]

You could get that error if your current directory is one that you do not have permission to write. Use pwd to find out what directory you are in, and cd to one you can write to.