mono2stim

 MONO2SIM transform monopolar stimulation into another stim pattern
   S = MONO2STIM(M, STIM) is the measurement corresponding to a
   stimulation and measurement pattern STIM, as created with e.g.
   MK_STIM_PATTERNS, obtained from a transformation of the monopolar
   measurments M. The monopolar stimulation pattern with which M was
   calculated must be
       MSP = mk_stim_patterns(E,R,'{mono}','{mono}', {'meas_current'},1);
   where E is the number of electrodes per ring and R is the number of
   rings. 
   
   STIM must use the same set of electrodes as MSP.
   
   M can be an EIDORS data struct with a 'meas' field, a Jacobian matrix, 
   or a matrix of voltages.

 See also MK_STIM_PATTERNS, STIM_MEAS_LIST, FWD_SOLVE, CALC_JACOBIAN

0001 function out = mono2stim(mat, stim)
0002 % MONO2SIM transform monopolar stimulation into another stim pattern
0003 %   S = MONO2STIM(M, STIM) is the measurement corresponding to a
0004 %   stimulation and measurement pattern STIM, as created with e.g.
0005 %   MK_STIM_PATTERNS, obtained from a transformation of the monopolar
0006 %   measurments M. The monopolar stimulation pattern with which M was
0007 %   calculated must be
0008 %       MSP = mk_stim_patterns(E,R,'{mono}','{mono}', {'meas_current'},1);
0009 %   where E is the number of electrodes per ring and R is the number of
0010 %   rings.
0011 %
0012 %   STIM must use the same set of electrodes as MSP.
0013 %
0014 %   M can be an EIDORS data struct with a 'meas' field, a Jacobian matrix,
0015 %   or a matrix of voltages.
0016 %
0017 % See also MK_STIM_PATTERNS, STIM_MEAS_LIST, FWD_SOLVE, CALC_JACOBIAN
0018 
0019 % (C) 2022 Bartek Grychtol. License: GPL version 2 or 3
0020 % $Id: mono2stim.m 6316 2022-04-21 11:14:35Z aadler $
0021     
0022     if nargin==1 && ischar(mat) && strcmp(mat, 'UNIT_TEST')
0023         do_unit_test; return
0024     end
0025     
0026     m2s = [];
0027     for i = 1:numel(stim)
0028         m2s = [m2s ; kron(stim(i).stim_pattern', stim(i).meas_pattern)];
0029     end
0030     if isstruct(mat) && isfield(mat, 'meas')
0031         out = mat;
0032         out.meas = m2s * mat.meas;
0033     else
0034         out = m2s * mat;
0035     end
0036 end
0037 
0038 function do_unit_test
0039 th= linspace(0,360,8+1); th(end)=[]; zz=0*th;
0040 epos = [th; zz+0.5]';
0041 fmdl = ng_mk_cyl_models(1,epos,0.1);
0042 fmdl.stimulation = mk_stim_patterns(8,1,'{mono}','{mono}', {'meas_current'},1);
0043 Jm= calc_jacobian(mk_image(fmdl,1));
0044 vm = fwd_solve(mk_image(fmdl,1));
0045 for SP=1:3
0046     for MP=1:3
0047         fprintf('SP=%d MP=%d\n',SP,MP);
0048         fmdl.stimulation = mk_stim_patterns(8,1,[0,SP],[0,MP],{'no_meas_current','rotate_meas'},1);
0049         Jo= calc_jacobian(mk_image(fmdl,1));
0050         Jx = mono2stim(Jm, fmdl.stimulation);
0051         unit_test_cmp('Equal',Jo,Jx, 10*eps);
0052         img = mk_image(fmdl,1);
0053         vo = fwd_solve(img);
0054         vx = mono2stim(vm, fmdl.stimulation);
0055         unit_test_cmp('Equal',vo.meas,vx.meas, 50*eps);
0056     end
0057 end
0058 end