# Using CubicSplineInterpolation on a vector (not on a Lazy Array)
**URL:** https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044
**Category:** New to Julia
**Created:** [May 23, 2020, 8:18pm UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044 "2020-05-23T20:18:52Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jovansam](https://discourse.julialang.org/u/jovansam)
#### Post date: [May 23, 2020, 8:18pm UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044/1 "2020-05-23T20:18:52Z")
I have a small problem that I can’t seem to solve regarding the use of CubicSplineInterpolation on a vector (rather than lazy array).
```nohighlight
using Interpolations, Plots
function spline_interpolation2()
#mygrid = range(-1.0, stop=1.0, length=5) # lazy array representation
mygrid = collect(range(-1.0, stop=1.0, length=5)) # vector representation
mypoints = abs.(mygrid)
#itp = interpolate((mygrid,),mypoints, Gridded(Constant()))
#itp = interpolate((mygrid,),mypoints, Gridded(Linear()))
#itp = LinearInterpolation(mygrid, mypoints, extrapolation_bc=Flat())
#itp = LinearInterpolation(mygrid, mypoints)
#itp = Spline1D(mygrid, mypoints, k=3, bc="nearest", s=0.0)
itp = CubicSplineInterpolation(mygrid, mypoints; bc=Line(OnGrid()), extrapolation_bc=Throw())
# interpolate at any point
myfinergrid = range(-1.0, stop=1.0, length=100)
itp.(myfinergrid)
plot(myfinergrid, [abs.(myfinergrid) itp.(myfinergrid)], label=["abs" "interplotion"])
end
spline_interpolation2()
```
When using Spline1D I get what I want. CubicSplineInterpolation returns a method error, though.
FYI: LinearInterpolation works, but it is not what I want to use. I am interested in Cubic Interpolation.
Thanks for the help.
---
### Author:  [@lungben](https://discourse.julialang.org/u/lungben)
#### Post date: [May 23, 2020, 8:46pm UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044/2 "2020-05-23T20:46:58Z")
Cubic Splines is not yet implemented on custom grids, see [Gridded Cubic Splines (WIP) by alexmorley · Pull Request #193 · JuliaMath/Interpolations.jl · GitHub](https://github.com/JuliaMath/Interpolations.jl/pull/193)
---
### Author:  [@jovansam](https://discourse.julialang.org/u/jovansam)
#### Post date: [May 24, 2020, 8:23pm UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044/3 "2020-05-24T20:23:29Z")
I see. Thanks. I will stick to Spline1D for the moment then.
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [May 25, 2020, 2:12am UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044/4 "2020-05-25T02:12:50Z")
> [@lungben](#):
>
> Cubic Splines is not yet implemented on custom grids
[GitHub - kbarbary/Dierckx.jl: Julia package for 1-d and 2-d splines](https://github.com/kbarbary/Dierckx.jl) supports this.
---
### Author:  [@jovansam](https://discourse.julialang.org/u/jovansam)
#### Post date: [May 27, 2020, 6:25am UTC](https://discourse.julialang.org/t/using-cubicsplineinterpolation-on-a-vector-not-on-a-lazy-array/40044/5 "2020-05-27T06:25:34Z")
Thanks at @stevengj. I indeed resorted to Dierckx.jl