atQuantDiff

atQuantDiff creates a quantum diffusion element

ELEM=ATQUANTDIFF(FAMNAME,DIFFMAT) uses the given diffusion matrix
   FAMNAME:   family name
   DIFFMAT:   Diffusion matrix

ELEM=ATQUANTDIFF(FAMNANE,RING) computes the diffusion matrix of the ring
   FAMNAME:   family name
   RING:      lattice without radiation

ELEM=ATQUANTDIFF(FAMNANE,RING,'orbit0',orbit) computes the diffusion 
                 matrix of the ring without computing the closed orbit
   orbit:     closed orbit at beginning of the ring 
              (this option is useful for the islands)

  The optional field Seed can be added. In that case, the seed of the
  random number generator is set at the first turn.
  ELEM=ATQUANTDIFF(FAMNANE,RING,'Seed',4)

See also quantumDiff

0001 function elem=atQuantDiff(fname,varargin)
0002 %atQuantDiff creates a quantum diffusion element
0003 %
0004 %ELEM=ATQUANTDIFF(FAMNAME,DIFFMAT) uses the given diffusion matrix
0005 %   FAMNAME:   family name
0006 %   DIFFMAT:   Diffusion matrix
0007 %
0008 %ELEM=ATQUANTDIFF(FAMNANE,RING) computes the diffusion matrix of the ring
0009 %   FAMNAME:   family name
0010 %   RING:      lattice without radiation
0011 %
0012 %ELEM=ATQUANTDIFF(FAMNANE,RING,'orbit0',orbit) computes the diffusion
0013 %                 matrix of the ring without computing the closed orbit
0014 %   orbit:     closed orbit at beginning of the ring
0015 %              (this option is useful for the islands)
0016 %
0017 %  The optional field Seed can be added. In that case, the seed of the
0018 %  random number generator is set at the first turn.
0019 %  ELEM=ATQUANTDIFF(FAMNANE,RING,'Seed',4)
0020 %
0021 %See also quantumDiff
0022 
0023 [rsrc,arg,method]=decodeatargs({[],'QuantDiffPass'},varargin);
0024 [method,rsrc]=getoption(rsrc,'PassMethod',method);
0025 [cl,rsrc]=getoption(rsrc,'Class','QuantDiff');
0026 [orb,rsrc]=getoption(rsrc,'orbit0',[]);
0027 if iscell(arg)
0028     [ring2,radindex]=atradon(arg);
0029     if ~isempty(orb)
0030         dmat=quantumDiff(ring2,radindex,orb);
0031     else
0032         dmat=quantumDiff(ring2,radindex);
0033     end
0034 else
0035     dmat=arg;
0036 end
0037 elem=atbaselem(fname,method,'Class',cl,'Lmatp',lmatp(dmat),rsrc{:});
0038 
0039     function lmatp = lmatp(dmat)
0040         %lmat does Cholesky decomp of dmat unless diffusion is 0 in
0041         %vertical.  Then do chol on 4x4 hor-long matrix and put 0's
0042         %in vertical
0043         try
0044             lmat66 = chol(dmat);
0045         catch
0046             lm=[chol(dmat([1 2 5 6],[1 2 5 6])) zeros(4,2);zeros(2,6)];
0047             lmat66=lm([1 2 5 6 3 4],[1 2 5 6 3 4]);
0048         end
0049         lmatp=lmat66';
0050     end
0051 end