What is the model file in svm-train command-line syntax? - libsvm

Question

I have used grid.py in LIBSVM and found the best parameter for my dataset
C -8.0 g -0.0625 CV- 63.82
Then I tried svm-train but I don't understand the syntax of the svm-train command
svm-train [options] training_set_file [model_file]
A model_File is need but grid.py only gave me a .out file. When I used this, it showed an error.
My question is:
Could you explain what the model file is, preferably using an example?
I am using LIBSVM on Debian (using the command-line).

Answer 1

You want command-lines like:
svm-train -C 8.0 -g 0.0625 training.data svm.model
svm-predict testing.data svm.model predict.out
The model file (svm.model) is just a place to store the model parameters learned by svm-train so that they can be later used for prediction. The model is created by svm-train, it is not produced by grid.py, and it is input to svm-predict. Therefore you can make any name you like to give to svm--train, so long as you give the same name to svm-predict. I often call the file something like model-C8.0-g0.0625 so I can later tell what it is.
A model file will look like this:
svm_type c_svc
kernel_type rbf
gamma 0.5
nr_class 2
total_sv 6164
rho -2.4768
label 1 -1
nr_sv 3098 3066
SV
2 1:-0.452773 2:-0.455573 3:-0.485312 4:-0.436805 ...
If you need to know more about the model file, see the LIBSVM FAQ