Banfac Banslv Bint4 Bintk Bspldr Bsplev Bsplpp Bsplvd Bsplvn Bvalue Interv Ppvalu

Ppvalu() Function Ppvalu ( C() As  Double, Xi() As  Double, Lxi As  Long, K As  Long, Ideriv As  Long, X As  Double, Inppv As  Long, Info As  Long  ) Evaluation of function or derivative value for PP (piecewise polynomial) form of B-spline Purpose This routine evaluates the PP (piecewise polynomial) representation (C(), Xi(), Lxi, K) of a B-spline at X for the function value on Ideriv = 0 or any of its derivatives on Ideriv = 1, 2, ..., K-1. The Taylor expansion about Xi(j-1) for X in the interval Xi[j-1] <= X < Xi(j) is evaluated (j = 1 to Lxi). Right limiting values (right derivatives) are obtained. Ppvalu will extrapolate beyond Xi(0) and Xi(Lxi). To obtain left limiting values (left derivatives) at a Xi(j), replace Lxi by by j-1 and set X = Xi(j), j = 1 to Lxi. Returns Double Value of the Ideriv-th derivative at X. Parameters [in] C() Array C(LC1 - 1, LC2 - 1) (LC1 >= K, LC2 >= Lxi) Right derivatives at break points. [in] Xi() Array Xi(LXi - 1) (LXi >= Lxi + 1) Break points. [in] Lxi Number of polynomial pieces. [in] K Order of the B-spline. (K >= 1) [in] Ideriv Order of the derivative. (0 <= Ideriv <= K - 1) Ideriv = 0 gives the B-spline value. [in] X Argument. (Xi(0) <= X <= Xi(Lxi)) [in,out] Inppv An initialization parameter. [in] Must be set to 1 when the first time Ppval is called. [out] Information for efficient processing after the initial call and Inppv must not be changed by the user. Distinct splines require distinct Inppv parameters. [out] Info = 0: Successful exit. = -1: The argument C() is invalid. = -2: The argument Xi() is invalid. = -3: The argument Lxi had an illegal value. (Lxi < 1) = -4: The argument K had an illegal value. (K < 1) = -5: The argument Ideriv had an illegal value. (Ideriv < 0 or Ideriv >= K) Reference SLATEC Example Program See example of Bsplpp.