chfdv chfev pchbs pchcm pchfd pchfe pchic pchim pchse pchsp

chfev() void chfev ( double  x1, double  x2, double  f1, double  f2, double  d1, double  d2, int  ne, double  xe[], double  fe[], int  next[], int *  info  ) Cubic Hermite function values Purpose This routine evaluates a cubic polynomial given in Hermite form at an array of points, i.e. evaluates the cubic polynomial determined by function values f1, f2 and derivatives d1, d2 on interval [x1, x2] at the points xe[j], j=1 to ne. While designed for use by pchfe, it may be useful directly as an evaluator for a piecewise cubic Hermite function in applications, such as graphing, where the interval is known in advance. Parameters [in] x1 Endpoint of interval of definition of cubic. (x1 != x2) [in] x2 Endpoint of interval of definition of cubic. (x1 != x2) [in] f1 Value of function at x1. [in] f2 Value of function at x2. [in] d1 Value of derivative at x1. [in] d2 Value of derivative at x2. [in] ne Number of evaluation points. (ne >= 1) [in] xe[] Array xe[lxe] (lxe >= ne) Points at which the function is to be evaluated. If any of the xe[] are outside the interval [x1, x2], a warning error is returned in next[]. [out] fe[] Array fe[lfe] (lfe >= ne) Values of the cubic function defined by x1, x2, f1, f2, d1, d2 at the points xe[]. [out] next[] Array next[lnext] (lnext >= 2) Number of extrapolation points. next[0] = number of evaluation points to left of interval next[1] = number of evaluation points to right of interval [out] info = 0: Successful exit = -2: The argument x2 had an illegal value (x2 = x1) = -7: The argument ne had an illegal value (ne < 1) Reference SLATEC (PCHIP)