RSPOLY2 |
Reduced set method for second order homogeneous polynomial kernel.
Synopsis:
red_model = rspoly2(model)
red_model = rspoly2(model,max_nsv)
Description:
It uses reduced set techique to reduce complexity
of the kernel expansion with second order homogeneous polynomial
kernel k(x,y) = (x'*y)^2 = kernel(x,y,'poly',2) .
The method was published in
J.C.Burges: Simplified Support Vector Decision Rules. ICML, 1996.
Input:
model [struct] Kernel expansion:
.Alpha [nsv x 1] Weights of kernel expansion.
.b [1x1] Bias.
.sv.X [dim x nsv] Support vectors.
.options.ker = 'poly'
.options.arg = [2 0]
max_nsv [1x1] Maximal number of new support vectors. If not given
then the new expansion approximates the original one exactly with
at most dim support vectors.
Output:
red_model [struct] Reduced kernel expansion:
red_model.Alpha [new_nsv x 1] New weights.
red_model.b [scalar] Bias.
red_model.sv.X [dim x new_nsv] New support vectors.
...
Example:
trn = load('riply_trn');
model = smo(trn,struct('ker','poly','arg',[2 0],'C',10));
red_model = rspoly2( model );
figure;
subplot(1,2,1); axis square; ppatterns(trn); psvm(model);
subplot(1,2,2); axis square; ppatterns(trn); psvm(red_model);
See also
RSRBF.
About: Statistical Pattern Recognition Toolbox
(C) 1999-2004, Written by Vojtech Franc and Vaclav Hlavac
Czech Technical University Prague
Faculty of Electrical Engineering
Center for Machine Perception
Modifications:
22-dec-2004, VF, header and comments added
28-nov-2003, VF