fitlag polcof polint polyvl

polyvl() void polyvl ( int  nder, double  xx, double *  yfit, double  yp[], int  n, double  x[], double  c[], double  work[], int *  info  ) Produces a polynomial interpolation Purpose This routine calculates the value of a polynomial and its first nder derivatives where the polynomial was produced by a previous call to polint. Parameters [in] nder The number of derivatives to be evaluated. (nder >= 0) [in] xx The argument at which the polynomial and its derivatives are to be evaluated. [out] yfit The value of the polynomial at xx. [out] yp[] Array yp[lyp] (lyp >= nder) The derivatives of the polynomial at xx of order 1 to nder. [in] n The number of data points (must remain unchanged between the call to polint and the call to polyvl). [in] x[] Array x[lx] (lx >= n) The array of abscissas (must remain unchanged between the call to polint and the call to polyvl). [out] c[] Array c[lc] (lc >= n) An array of information produced by subroutines polint (must remain unchanged between the call to polint and the call to polyvl). [out] work[] Array work[lwork] (lwork >= 2*n) Work array. (Not referenced if nder = 0) [out] info = 0: Successful exit = -1: The argument nder had an illegal value (nder < 0) = -5: The argument n had an illegal value (n < 1) Reference SLATEC