Richard Stapenhurst

Hi Honza,
if you are referring to the case where data is not linearly separable, then it is true that the computation of the boundary and support vectors may seem strange.

Typically, we would construct an SVM with some tolerance for misclassified data; for example, we could compute a 'soft margin' (See Vapnik and Cortes, 1995), which optimises a trade-off between the maximum margin decision boundary and a small penalty for misclassification. In my program, I have set the misclassification penalty to be very large - since this can affect the position of the decision boundary even when data is linearly separable. I do this so that you can see the optimal separating hyperplane.

Obviously this is not representative of how you would solve a real non linearly separable problem - if you suspect that data is noisy, it would be appropriate to change the 'C' parameter in a soft-margin SVM. Alternatively, if you suspect that data is complex and non-linear, it may be better to use a non-linear kernel (e.g. rbf).

Regardless of where data is linear and/or separable, you should find that some data points that are correctly classified will be support vectors. The support vectors correspond to the data points that actually define where the decision boundary is. They comprise any misclassified datapoints (which will correspond to penalty terms in the soft-margin problem), and all the correctly classified datapoints which lie exactly the minimum distance away from the margin.

I hope this answers your question.

Hi Bryant,
As the description says, the pre-processing only works for scripts. I could modify it to accommodate functions/classes, but I'd be surprised if this was regularly useful.
However, it is possible to manually add a progress bar in non-script scenarios as described in the first paragraph of the description.
I will add support for pre-processing of functions to my to-do list :)

How can I run it.Who can tell me.Thank you.

I find this code very inetrsting,I want to add an other data with inputs is a matrix(n,m) with n>2 and the output is a vector(1,m). But I find error of size of matrix