Ordinary polynomials

E02ADF finds the fitting Chebyshev series minimising r.m.s. The Chebyshev series is equivalent to an ordinary polynomial, but cannot be extrapolated. The polynomial is evaluated by E02AEF or E02AKF. In the latter routine the Chebyshev coefficients can be one column of an array. It will also take the real-world x argument instead of the normalised x-bar argument within the range $-$1 ... +1.

In this library, PDA_DPOLFT fits an ordinary polynomial as a sum of orthogonal polynomials. The representation returned is somewhat special. It can be converted to coefficients of a Taylor series with PDA_DPCOEF or directly evaluated with PDA_DP1VLU. PDA_DP1VLU will return in one call as many derivatives as requested.