Hello,
I'm not sure what you mean by all the points below. But it's perhaps
explaining a bit more about the "nearby points to check" feature in the
peak find parameter dialog. The two choices are "+-1 in at most one dim"
and "+-1 allowed in any dim". To explain what these rather turgid phrases
mean, consider a 2D. If we want to know whether a grid point (i, j) is a
local maximum, for example, the first choice above looks at grid points
(i-1, j)
(i+1, j)
(i, j-1)
(i, j+1)
and if the values at these points are all less than or equal to that at
(i, j) then we are deemed to have a local maximum at (i, j). You will
notice that for those points either x is +-1 or y is +-1 the center
point but not both. The second choice looks at not only those but also
the grid points
(i-1, j-1)
(i-1, j+1)
(i+1, j-1)
(i+1, j+1)
and so both x and y can be +-1 at the same time. (These are the
"diagonal" points.) In general in N dimensions the first choice has 2N
checks and the second one has 3^N - 1 checks (^ means power) so is much
more expensive.
I guess in theory you could have even more stringent checks (for
maximality) going past this first layer outwards, but there does not seem
much point given that in the usual view the first layer completely
"surrounds" the center.
Wayne
On Mon, 14 Feb 2005, Karthik wrote:
> Thanks a lot tim..
>
> i am analysing two similar noesy spectra, because they have a mild
> difference in experimental parameters their shifts have shifted marginally
> (but not at the same rate throughout the spectrum, hence i cannot move axis
> by constant ppm)... So if i have to use the peak copy function of CCPN, they
> wont find a peak automatically.. this is my problem.
>
> You told me that the peak picking parameter is based on the refrence
> spectrum.. Is there any peak matching parameter? the peak find parameter
> dialog has an option where i can choose between +_ 1 point in one dimention
> or all dimentions.. but the value 1 is fixed. is it possible to vary this?
> so that i can choose the stringency of matching.
>
> thanks again
> karthik
>
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