Home > sfa_tk > sfa > sfa_getHf.m



SFA_GETHF Return a SFA function as a quadratic form.


function [H,f,c]=sfa_getHf(hdl, nr, where)


 SFA_GETHF Return a SFA function as a quadratic form.
   [H,f,c] = SFA_GETHF(HDL, NR, WHERE) returns function number NR in the
   sfa object referenced by HDL in the form of a quadratic form
            q(x) = 1/2*x'*H*x + f'*x + c
   Of course, this only works if a quadratic expansion was used during

   The quadratic form can lie in different spaces, i.e. it can receive
   as input preprocessed or non-preprocessed vectors. This is specified
   by setting the argument WHERE. The quadratic form lies
    - in the preprocessed space for WHERE==0 (e.g. the whitened space if
      the preprocessing type is PCA)
    - in the PCA space (i.e. projected on the principal components but
      not whitened, works only if PCA was used for preprocessing) for
    - in the input, mean-free space for WHERE==2
    - in the input space for WHERE==3
   In general you will need to set WHERE to 2 or 3, but working in the
   preprocessed spaces can often drastically improve the speed of

   See also SFA2_CREATE


This function calls: This function is called by:
Generated on Tue 10-Feb-2004 16:00:52 by m2html © 2003