chfdv chfev pchbs pchcm pchfd pchfe pchic pchim pchse pchsp

pchcm() void pchcm ( int  n, double  x[], double  f[], double  d[], int  incfd, int  skip, int  ismon[], int *  info  ) Monotonicity check for piecewise cubic Hermite function Purpose This routine checks the piecewise cubic Hermite function defined by n, x[], f[], d[] for monotonicity. 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) Function values. f[i*incfd] is the value corresponding to x[i] (i = 0 to n - 1). [in] d[] Array d[ld] (ld >= incfd*(n - 1) + 1) Derivative values. d[i*incfd] is the value corresponding to x[i] (i = 0 to n - 1). [in] incfd Increment between successive values in f[] and d[]. (incfd >= 1) [in] skip Logical variable which should be set to true (1) if the user wishes to skip checks for validity of preceding parameters, or to false (0) otherwise. This will save time in case these checks have already been performed (say, in pchim, pchic, pchsp or pchse). [out] ismon[] Array ismon[lismon] (lismon >= n) An integer array indicating on which intervals the piecewise cubic Hermite function defined by n, x[], f[], d[] is monotonic. For data interval [x[i], x[i+1]] (i = 0 to n-2),   ismon[i] = -3 if function is probably decreasing   ismon[i] = -1 if function is strictly decreasing   ismon[i] = 0 if function is constant   ismon[i] = 1 if function is strictly increasing   ismon[i] = 2 if function is non-monotonic   ismon[i] = 3 if function is probably increasing ismon[n-1] indicates whether the entire function is monotonic on [x[0], x[n-1]]. [out] info = 0: Successful exit = -1: The argument n had an illegal value (n < 2) = -2: The argument x[] had an illegal value (not strictly increasing) = -5: The argument incfd had an illegal value (incfd < 1) Reference SLATEC (PCHIP)