double Frequency::kernelF(double i,double f,double M)
{
if(i==M/2)
return kernel0(f);
return sin(2*M_PI*f*(i-M/2))/(i-M/2)
*(0.42-0.5*cos(2*M_PI*i/M)+0.08*cos(4*M_PI*i/M));
}
//at zero omega (to exclude zeros in denominator)
double delta0(gsl_vector* Q)//omega_center is defined in calculation of vector Q
{
int i;
double result=0.0;
for(i=0;i<Q->size;i++)
{
result+=gsl_vector_get(Q,i)*kernel0(i+1);
}
return result;
}
