sampling twiss function like in atplot

[lnadolski]

Dear all,

I am looking for a function to get the twiss functions with a refined sampling rate as in the function atplot when with specify a s-range.

Is there a way to get, let us say, the beta function every 10 cm along the lattice ?

If I play with the variable curve from curve = aplot(myring), I can get the data but this is a little bit painful.

Thank you for your suggestions,

Laurent.

[lfarv]

Hi @lnadolski. In Matlab, I don't think there is a function for splitting a portion of a ring in small slices. So the easiest solution is probably to extract from atbaseplot the few lines doing that and building a new function. It's in atbaseplot, lines 106-109, converting ring0 into ring:

% Split the ring
elmlength=findspos(ring0(el1:el2-1),el2-el1+1)/npts;
r2=cellfun(@splitelem,ring0(el1:el2-1),'UniformOutput',false);
ring=cat(1,ring0(1:el1-1),r2{:},ring0(el2:elt0));

and lines 140-150:

    function newelems=splitelem(elem)
        if isfield(elem,'Length') && elem.Length > 0
            nslices=ceil(elem.Length/elmlength);
            if ~KeepAxis
                newelems=atdivelem(elem,ones(1,nslices)./nslices);
            else
                newelems=atdivelem(elem,ones(1,nslices)./nslices,'KeepAxis');
            end
        else
            newelems={elem};
        end
    end

el1 and el2 are the beginning and end indices of the region to split, elmlength is the (maximum) slice length. As each element is splitted into an integer number of identical slices, the slice length is not uniform (so you 10 cm would be a maximum length).

To be noted: in the more recent pyAT, the Lattice object has a method for splitting lattice elements within a range of interest. So if you (or anyone else) feel like doing the same in Matlab, you are welcome!