SVMCLASS |
Support Vector Machines Classifier.
Synopsis:
[y,dfce] = svmclass( X, model )
Description:
[y,dfce] = svmclass( X, model ) classifies input vectors X
into classes using the multi-class SVM classifier
y(i) = argmax f_j(X(:,i))
j=1..nfun
where f_j are linear functions in the feature space given
by the prescribed kernel function (options.ker, options.arg).
The discriminant functions f_j are determined by
.Alpha [nsv x nfun] ... multipliers associated to SV
.b [nclass] ... biases of discriminant functions.
.sv.X [dim x nsv] ... support vectors.
See 'help kernelproj' for more info about valuation of the
discriminant functions f_j.
In the binary case nfun=1 the binary SVM classifier is used
y(i) = 1 if f(X(:,i) >= 0
= 2 if f(X(:,i) < 0
where f is the disrimiant function given by Alpha [nsv x 1],
b [1x1] and support vectors sv.X.
Input:
X [dim x num_data] Input vectors to be classified.
model [struct] SVM classifier:
.Alpha [nsv x nfun] Multipliers associated to suport vectors.
.b [nfun x 1] Biases.
.sv.X [dim x nsv] Support vectors.
.options.ker [string] Kernel identifier.
.options.arg [1 x nargs] Kernel argument(s).
Output:
y [1 x num_data] Predicted labels.
dfce [nfun x num_data] Values of discriminant functions.
Example:
trn = load('riply_trn');
model = smo(trn,struct('ker','rbf','arg',1,'C',10));
tst = load('riply_tst');
ypred = svmclass( tst.X, model );
cerror( ypred, tst.y )
See also
SMO, SVMLIGHT, SVMQUADPROG, KFD, KFDQP, MVSVMCLASS.
About: Statistical Pattern Recognition Toolbox
(C) 1999-2003, Written by Vojtech Franc and Vaclav Hlavac
Czech Technical University Prague
Faculty of Electrical Engineering
Center for Machine Perception
Modifications:
14-may-2004, VF
09-May-2003, VF
14-Jan-2003, VF