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; (20093.75, « »)

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

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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
    • 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
    • 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...

      jectType=file>

      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