Can not find weight in model when i want to build a SVM-RFE model

[MosBest]

Hello!
I want to bulid a SVM model about recursive feature elimination!
However , after I use the demo model=svmtrain(instances[:, 1:2:end], vectorlabels[1:2:end]);, i could not find the Coefficient of the features.

there are 3 class and 4 feature in The data about iris. So i think i can get 12 Coefficient of the features. Could you tell me where are they?
Thank you very much!

[barucden]

What do you mean by "the Coefficient of the features"? The features are stored in instances.