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Topic: how to make input size the same as output in interp2
Replies: 4   Last Post: May 4, 2013 6:48 AM

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hanciong awesome

Posts: 21
Registered: 1/11/12
Re: how to make input size the same as output in interp2
Posted: Mar 7, 2013 3:37 PM
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But then what should I do if I want to integrate this interpolation function? The quad2d or integral2 or whatever make input of x and y arbitrarily; I can't force them to expand x input or y input to have same size.

"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <kdus7o$9he$1@newscl01ah.mathworks.com>...
> "hanciong" wrote in message <kdufmg$ha6$1@newscl01ah.mathworks.com>...
> >how should I modify this such that the size of the output is the same as input, if either x or y is scalar? Thanx
>
> You can't. When calling interp2(..., x, y); with the interpolation points x and y are scalar/vectors with different sizes, the inputs x and y are first expanded on grid as following:
>
> [X Y] = meshgrid(x(:),y(:)) % x varying 2nd dimension and x first
> z = interp2(..., X, Y);
>
> Therefore
> 1) if x is scalar, the output is vertical regardless y;
> 2) if y is scalar, the output is horizontal regardless x.
>
> This behavior is documented.
>
> If you want to force the result to be horizontal or vertical vectors, you must expand x, y in the same size:
>
> fuint([1 1 1],[2,3,4])
> fuint([2;3;4],[1;1;1])
>
> % Bruno




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