### Tags: bound, extrapolation, function, inputvalues, interp1, interp2, interpn, matlab, programming

# extrapolation

On Programmer » Matlab

2,641 words with 3 Comments; publish: Wed, 07 May 2008 22:00:00 GMT; (20050.78, « »)

I am looking for an extrapolation function. The same as interp1,

interp2, or interpn, but that would also work for out of bound input

values.

Thanks for any help,

Serge

*http://matlab.todaysummary.com/q_matlab_16766.html*

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- 3 Comments
- Serge wrote:
> I am looking for an extrapolation function. The same as interp1,

> interp2, or interpn, but that would also work for out of bound input

> values.

I know INTERP1 takes an extra 'extrap' argument after

the method argument. I suspect the others do as well.

- Randy

#1; Wed, 07 May 2008 22:02:00 GMT

- Serge wrote:
- No they don't, and that's precisely my problem...
Serge

Randy Poe wrote:

> Serge wrote:

> I know INTERP1 takes an extra 'extrap' argument after

> the method argument. I suspect the others do as well.

> - Randy

#2; Wed, 07 May 2008 22:03:00 GMT

- No they don't, and that's precisely my problem...
- Serge wrote:
>

> No they don't, and that's precisely my problem...

> Serge

> Randy Poe wrote:

> interp1,

bound

> input

>

Interpne was written to allow extrapolation for

the general n-d case.

<http://www.mathworks.com/matlabcent...

But I intentionally chose not to implement

a 'cubic' extrapolant. Sorry about that.

Extrapolation is nasty enough without that

complexity. For example, even a bilinear

interpolant is quadratic in extrapolation

if you look in the right direction.

John

"In the space of one hundred and seventy-six years the Lower

Mississippi has shortened itself two hundred and forty-two

miles. That is an average of a trifle over one mile and a

third per year. Therefore, any calm person, who is not

blind or idiotic, can see that in the Old Olitic Silurian

Period, just a million years ago next November, the Lower

Mississippi River was upward of one million three hundred

thousand miles long, and stuck out over the Gulf of Mexico

like a fishing rod. And by the same token any person can

see that seven hundred and forty-two years from now the

Lower Mississippi will be only a mile and three quarters

long, and Cairo and New Orleans will have joined their

streets together, and be plodding comfortably under a

single mayor and a mutual board of aldermen. There is

something fascinating about science. One gets such

wholesome returns of conjecture out of such a trifling

investment of fact."

Mark Twain, Life on the Mississippi

#3; Wed, 07 May 2008 22:04:00 GMT

- Serge wrote: