WPchfe WPchia WPchse

WPchse() Function WPchse ( N As  Long, X As  Variant, Y As  Variant  ) Piecewise cubic Hermite spline interpolation ("not a knot" condition) Purpose WPchse computes the derivatives needed to determine the Hermite representation of the cubic spline interpolant to given data, with the default boundary conditions ("not a knot" condition). The resulting piecewise cubic spline function may be evaluated by WPchfe. Returns N x 1 Column 1 Rows 1 to N Cubic spline coefficients Parameters [in] N Number of data points. (N >= 2) [in] X (N) The abscissas of the data points in strictly increasing order. [in] Y (N) The ordinates of the data points. Reference SLATEC (PCHIP) Example Interpolate the following natural logarithm table by WPchse. And compute ln(0.115) and ln(0.125) by WPchfe. x ln(x) ------ -------- 0.10 2.3026 0.11 2.2073 0.12 2.1203 0.13 2.0402 ------ --------