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Topic: interpolate
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Posts: 9,497
Registered: 6/7/07
Re: interpolate
Posted: Dec 27, 2012 10:55 AM
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On 12/26/2012 7:45 PM, maryam wrote:
> dpb <> wrote in message <kbg5ol$ugl$>...
>> On 12/26/2012 5:03 PM, maryam wrote:
>> > dpb <> wrote in message <kbfhar$1lo$>...

>> >> doc interp1
>> >>

>> >> >> X = 0:10; V = sin(X); Xq = 0:.25:10;
>> >> >> Vq = interp1(X,V,Xq);


>> > thank you very much for your answer but I mean we have a matrix n-by-m:
>> > assume M= [a b c;d e f; g h i]
>> > I want to interpolate its rows so that is equal to
>> > M=[a a+d a+2d a+3d ... 7d b b+d ... b+7d c... c+7d ; d... d+7d...

>> f+7d ;
>> > g ... i+7d]
>> > Can you explain me how I could do it?

>> I'm virtually certain you asked this same question some days ago and I
>> told you then the same thing...
>> Use interp1() as the above example w/ an interpolating vector of the
>> points at which you want interpolants. Here's why I think I remember
>> the question and the response, as I pointed out then, since interp1()
>> works on columns you'll need to transpose, interpolate, then transpose
>> back.
>> I can't interpret the above [a a+d a+2d ... ) precisely but assuming d
>> here is a different 'd' than that of the value in the original M(2,1)
>> and is just a delta then the interpolant would seem to be
>> linspace(0,N*d,N+1) where N is the number of intervals (7 above) added
>> to a, b, c, ..., etc.


> thank you so much, I'm Beginner in matlab,
> I apologize for my request
> Is it possible give me matlab code of my question?
> I couldn't use 'for' command or M(:,columns) ...
> my matrix is 1000-by-1200 d=delta=1/16
> its values (arrays) is arbitrary here

That's identical to the example I gave except on an array instead of a
vector...and a still-to-be-determined precisely interpolant.

What does the 1/16 delta refer to--is it a constant or a fraction of the
distance between columns, or what? Your description isn't precise (or
at least I can't decipher what it is you want clearly enough to actually
write a piece of specific code).

Can you give a very small example of a dataset that you could compute
the desired result of by hand? It wouldn't have to be but one row and a
few values to illustrate what you're actually trying to do...


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