Cubic (and PCHIP) interpolation with irregularly spaced points.
This package is not licensed. I (Forrest Gasdia) have approval to use this code in any non-commercial package from Steve Turley (see private email March 6, 2021). Beginning with v0.0.2
of this package I made significant changes to the source code.
Turley, R. Steven, "Cubic Interpolation with Irregularly-Spaced Points in Julia 1.4" (2018). Faculty Publications. 2177. https://scholarsarchive.byu.edu/facpub/2177