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## What did I do wrong with this funtion? - Implementing msplines and ispli

 From: Corrado Subject: What did I do wrong with this funtion? - Implementing msplines and isplines in Octave Date: Wed, 16 Sep 2009 09:10:37 +0100 User-agent: KMail/1.11.4 (Linux/2.6.28-13-generic; KDE/4.2.4; x86_64; ; )

```Dear friends,

I am trying to implement in Octave the two spline families as in the
documentation here below attached. I am a newbie to Octave, and this is my
first function.

I built the function:

function retspline = mspline (i,x,k,t)
# i is the spline index in the family
# x is the variable
# t is the vector of knots, t(h) is the h-th knot
# k is the Mspline degree

I=i

if(k==1)

if(x<t(i+1) & x>=t(i))
td=t(i+1)-t(i)
M=1/td
else
M=0
endif

else

kk=(k-1)

if (x>=t(i) & x<t(i+k))
M=k*((x-t(i))*mspline(i=I,x=x,k=kk,t=t)+(t(i+k)-
x)*mspline(i=(I+1),x=x,k=kk,t=t))/((k-1)*(t(i+k)-t(i)))
elseif (x<t(i) | x>=t(i+k))
M=0
endif

endif

retspline=M

endfunction

but for some reason it does not work ....

I add that I am a newbie with Octave, please do not shut me.

What did I do wrong?

Best,
--

Global Climate Change & Biodiversity Indicators
Area 18,Department of Biology
University of York, York, YO10 5YW, UK
Phone: + 44 (0) 1904 328645, E-mail: address@hidden

```

mspline
Description: PNG image

ispline.png
Description: PNG image