chfdv chfev pchbs pchcm pchfd pchfe pchic pchim pchse pchsp

pchse() void pchse ( int  n, double  x[], double  f[], double  d[], int  incfd, double  work[], int  lwork, int *  info  ) Piecewise cubic spline interpolation ("not a knot" condition) Purpose This routine computes the derivatives needed to determine the Hermite representation of the cubic spline interpolant to given data, with with the default boundary conditions ("not a knot" condition). The resulting piecewise cubic spline function may be evaluated by pchfe or pchfd. Parameters [in] n Number of data points. (n >= 2) [in] x[] Array x[lx] (lx >= n) Independent variable values. The elements of x[] must be strictly increasing. [in] f[] Array f[lf] (lf >= incfd*(n - 1) + 1) Dependent variable values to be interpolated. f[i*incfd] is the value corresponding to x[i] (i = 0 to n - 1). [out] d[] Array d[ld] (ld >= incfd*(n - 1) + 1) Derivative values at the data points. These values will determine the cubic spline interpolant with the requested boundary conditions. The value corresponding to x[i] is stored in d[i*incfd] (i = 0 to n - 1). No other entries in d[] are changed. [in] incfd Increment between successive values in f[] and d[]. This argument is provided primarily for 2-D applications. (incfd >= 1) [out] work[] Array work[lwork] Work array. [in] lwork The dimension of the array work[] (lwork >= 2*n) [out] info = 0: Successful exit = -1: The argument n had an illegal value (n < 2) = -2: The argument x had an illegal value (x[] is not strictly increasing) = -5: The argument incfd had an illegal value (incfd < 1) = -7: The argument lwork had an illegal value (lwork < 2*n) Reference SLATEC (PCHIP) (Driver for pchsp)