double wnorm(std::vector<int> y, std::vector<double> alpha, std::vector<std::vector<double>> traindata, int maxn, std::vector<double> w, std::vector<std::vector<int>> feattrain) {
std::vector<double> wtemp(w.size());
std::fill(wtemp.begin(),wtemp.end(),0);
for(int i=0;i<y.size();i++) {
int h=feattrain[i].size();
for(int j=0;j<h;j++){
wtemp[feattrain[i][j]]+=alpha[i]*y[i]*traindata[i][j];
}
}
double norm=0;
for(int k=0;k<w.size();k++) {
wtemp[k] -= w[k];
}
for(int k=0;k<w.size();k++) {
norm+= wtemp[k]*wtemp[k];
}
return norm;
}
/*************************************************************************
Rational barycentric interpolation without poles
The subroutine constructs the rational interpolating function without real
poles. It should be noted that the barycentric weights of the interpolant
constructed are independent of the values of the given function.
Input parameters:
X - interpolation nodes, array[0..N-1].
N - number of nodes, N>0.
D - order of the interpolation scheme, 0 <= D <= N-1.
Output parameters:
W - array of the barycentric weights which can be used in the
BarycentricInterpolate subroutine. Array[0..N-1]
Note:
this algorithm always succeeds and calculates the weights with close
to machine precision.
-- ALGLIB PROJECT --
Copyright 17.06.2007 by Bochkanov Sergey
*************************************************************************/
void buildfloaterhormannrationalinterpolant(ap::real_1d_array x,
int n,
int d,
ap::real_1d_array& w)
{
double s0;
double s;
double v;
int i;
int j;
int k;
ap::integer_1d_array perm;
ap::real_1d_array wtemp;
ap::ap_error::make_assertion(n>0, "BuildRationalInterpolantWithoutPoles: N<=0!");
ap::ap_error::make_assertion(d>=0&&d<=n, "BuildRationalInterpolantWithoutPoles: incorrect D!");
//
// Prepare
//
w.setbounds(0, n-1);
s0 = 1;
for(k = 1; k <= d; k++)
{
s0 = -s0;
}
perm.setbounds(0, n-1);
for(i = 0; i <= n-1; i++)
{
perm(i) = i;
}
tagsortfasti(x, perm, n);
//
// Calculate Wk
//
for(k = 0; k <= n-1; k++)
{
//
// Wk
//
s = 0;
for(i = ap::maxint(k-d, 0); i <= ap::minint(k, n-1-d); i++)
{
v = 1;
for(j = i; j <= i+d; j++)
{
if( j!=k )
{
v = v/fabs(x(k)-x(j));
}
}
s = s+v;
}
w(k) = s0*s;
//
// Next S0
//
s0 = -s0;
}
//
// Reorder W
//
wtemp.setbounds(0, n-1);
ap::vmove(&wtemp(0), &w(0), ap::vlen(0,n-1));
for(i = 0; i <= n-1; i++)
{
w(perm(i)) = wtemp(i);
}
}