scipy.interpolate.pchip_interpolate(xi, yi, x, der=0, axis=0)[source]

Convenience function for pchip interpolation. xi and yi are arrays of values used to approximate some function f, with yi = f(xi). The interpolant uses monotonic cubic splines to find the value of new points x and the derivatives there.

See PchipInterpolator for details.


xi : array_like

A sorted list of x-coordinates, of length N.

yi : array_like

A 1-D array of real values. yi‘s length along the interpolation axis must be equal to the length of xi. If N-D array, use axis parameter to select correct axis.

x : scalar or array_like

Of length M.

der : integer or list

How many derivatives to extract; None for all potentially nonzero derivatives (that is a number equal to the number of points), or a list of derivatives to extract. This number includes the function value as 0th derivative.

axis : int, optional

Axis in the yi array corresponding to the x-coordinate values.


y : scalar or array_like

The result, of length R or length M or M by R,