NESSi  v1.0.2 The NonEquilibrium Systems Simulation Library

◆ poly_interpolation()

template<typename T = double>
 T integration::Integrator< T >::poly_interpolation ( int alpha, int l )
inline

Returns the the weight needed for polynomial interpolation.

Purpose

The $$k$$-th order approximation polynomial $$P(x)$$ through function values $$\{(x_l,f(x_l),l=0,\dots,k)\}$$ with $$x_{l+1}-x_{l}=h$$ is given by

\begin{align*} P(x) = \sum^k_{\alpha=0}\sum^k_{l=0} c_{\alpha,l}\, \left(\frac{x}{h}\right)^\alpha f(x_l) \end{align*}

poly_interpolation returns the coeffient $$c_{\alpha,l}$$ for given indicies $$\alpha,l$$.

Parameters
 alpha First index of coefficients. l Second index of coefficients.

Definition at line 262 of file integration.hpp.

262 {return poly_interpolation_[alpha*(k_+1)+l];}