[R] Splines

vito muggeo
Fri, 05 Oct 2007 09:01:15 -0000

As reported in ?spline, you should use splinefun() instead.

ff<-splinefun(x,y)
ff(x0)

where x0=5.25 is your case.

best,

vito


stat stat ha scritto:
> I want to fit a cubic spline of x on y. where :
>
>   x
>  [1] 467 468 460 460 450 432 419 420 423 423
> y
>  [1]  1  2  3  4  5  6  7  8  9 10
>
>   using the syntax
>
>   spline(y, x)
>
>   I got following output :
>
>   $x
>  [1]  1.000000  1.310345  1.620690  1.931034  2.241379  2.551724  2.862069
>  [8]  3.172414  3.482759  3.793103  4.103448  4.413793  4.724138  5.034483
> [15]  5.344828  5.655172  5.965517  6.275862  6.586207  6.896552  7.206897
> [22]  7.517241  7.827586  8.137931  8.448276  8.758621  9.068966  9.379310
> [29]  9.689655 10.000000
>   $y
>  [1] 467.0000 469.5381 469.8643 468.4865 465.9444 463.0284 460.6479
459.6560
>  [9] 459.8737 460.2296 459.6313 457.4921 454.0094 449.4482 444.1040
438.3613
> [17] 432.6204 427.2892 422.8183 419.6733 418.2646 418.3633 419.3283
420.5202
> [25] 421.5768 422.4555 423.1312 423.5419 423.5480 423.0000
>
>   Now I want to get what is the value of y at x = 5.25. Can anyone tell me
how to find that?
>
>
>
> thanks in advance
>
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--
===================================Vito M.R. Muggeo
Dip.to Sc Statist e Matem `Vianelli'
Universit? di Palermo
viale delle Scienze, edificio 13
90128 Palermo - ITALY
tel: 091 6626240
fax: 091 485726/485612