>>>>> David Winsemius <dwinsem...@comcast.net>
>>>>> on Sat, 1 Dec 2012 09:25:42 -0700 writes:
> On Dec 1, 2012, at 5:09 AM, Steve Stephenson wrote:
>> Hallo, I'm facing a problem and I would really appreciate
>> your support. I have to translate some Matalb code in R
>> that I don't know very well but I would like to. I have
>> to interpolate 5 point with a cubic spline function and
>> then I expect my function returns the Y value as output a
>> specific X value inside the evaluation range. Let's
>> suppose that: 1- *X = [-10, -5, 0, 5, 10]* 2 - *Y = [12,
>> 10, 8, 7, 6]* 3 - *I have to interpolate with a cubic
>> spline assuming x=11*
>>
>> In Matlab I used this function:
>>
>> *y = interp1(X, Y, x, "cubic"); *
>>
>> How can I do the same in R? Many thanks in advance for
>> your reply and support!
> splinefun( x = c(-10, -5, 0, 5, 10), y = c(12, 10, 8, 7, 6),
method="natural")(11) [1] 5.785714
Yes, indeed, or simple spline(....)
but definitely *no* need to use a function from an extra CRAN
package .. as someone else ``erronously'' suggested.
Note that
spline() and splinefun()
together with
approx() and approxfun()
are among the several hundred functions that were already
part of "pre-alpha" R, i.e., before R had a version number or *any* packages ...
and yes, the README then started with the two lines
| R Source Code (Tue Jun 20 14:33:47 NZST 1995)
| Copyright 1993, 1994, 1995 by Robert Gentleman and Ross Ihaka
and it would be *really* *really* great
if people did not add stuff to their packages that has
been part of R for longer than they have even heard of R.
Martin Maechler, ETH Zurich
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