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Topic: interpolate
Replies: 12   Last Post: Dec 31, 2012 9:33 AM

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dpb

Posts: 7,876
Registered: 6/7/07
Re: interpolate
Posted: Dec 26, 2012 7:46 PM
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On 12/26/2012 5:03 PM, maryam wrote:
> dpb <none@non.net> wrote in message <kbfhar$1lo$1@speranza.aioe.org>...
>> On 12/26/2012 12:29 PM, maryam wrote:
>> ...

>> > how could I interpolate rows of a matrix so that original value of rows
>> > don't change?

>>
>> Didn't we do this before the holidays?????
>>
>> doc interp1
>>

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

>> ans =
>> 1

>> >>
>>
>>
>> What else do you need????

> ---------------------------------------------------
> This question has already been answered?
> I searched but I didn't find it
> 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.

--





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