Is there a Cubic Spline Interpolation method implemented in J?

I'm not familiar myself, but I do have all the packages installed, so

$ rg -l -i spline  /usr/share/j/9.02/ -g '*.ijs'
/usr/share/j/9.02/addons/math/misc/spline.ijs
/usr/share/j/9.02/addons/stats/rlibrary/manifest.ijs
/usr/share/j/9.02/addons/stats/rlibrary/splines.ijs
/usr/share/j/9.02/addons/stats/rlibrary/test_splines.ijs
/usr/share/j/9.02/addons/math/misc/manifest.ijs
/usr/share/j/9.02/addons/graphics/plot/jzplot.ijs
/usr/share/j/9.02/addons/demos/wdplot/plexam.ijs

math/misc/spline and stats/rlibrary/splines look good, the latter though is interfacing with R. The former begins with an imlementation:

NB. =========================================================
NB.*cubicspline v Calculate cubic spline
NB.
NB. y is: 2-row matrix  x ,: f(x)
NB.
NB. result: x values;coefficient matrix,one row per interval.
cubicspline=: 3 : 0
...

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