Issues for addcoupling function error

[tingguangli]

Dear Developer,

I have an issue when I run the previous SpinW code (working great about 2 years ago) to calculate the spin wave dispersion, the addcoupling function return the error:
Error using spinw/addcoupling (line 236)
No matrix assigned, since no bond fulfilled the given conditions!

Error in MnO_spinwave (line 67)
MnO.addcoupling('mat','Ja','bond',1,'atom',{'Mn2','Mn2'});
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I have uploaded the matlab script as a txt file. I am using MATLAB version 2024b (Mac) and re-installed the SpinW recently and run the run_test.m, but it has the following error:
Error using mex
Supported compiler not detected. For options, visit
https://www.mathworks.com/support/compilers.

Error in sw_mex (line 89)
mex('-v','-largeArrayDims','eig_omp.cpp', 'CXX_FLAGS="-Xclang -fopenmp -pthread"', ...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in run_tests (line 43)
sw_mex('compile', true, 'test', false, 'swtest', false);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Could you give me any advice on those issues? Thanks a lot!

Best Regards,
Tingguang
Physics PhD Candidate at Duke University
Delaire Research Group

MnO_spinwave.txt

[RichardWaiteSTFC]

Hi Tingguang, thanks for getting in touch.
I have run your script and can reproduce the error on running line 67

MnO.addcoupling('mat','Ja','bond',1,'atom',{'Mn2','Mn2'});

However, I think the current behaviour in SpinW is correct (a few stricter checks/bugs were ironed out in #85 ).
If you look at the bond table for your system

 idx     subidx         dl                    dr               length    matom1     idx1    matom2     idx2                    matrix                
    ____    ______    _____________    _______________________    ______    _______    ____    _______    ____    ______________________________________

       1      1       1     0     0     0.25        0    -0.25    3.144     {'Mn1'}      7     {'Mn1'}      1     {0×0 char}    {0×0 char}    {0×0 char}
       2      1       1     0     0     0.25    -0.25        0    3.144     {'Mn2'}      8     {'Mn1'}      1     {0×0 char}    {0×0 char}    {0×0 char}

You can see that the bond with index 1 is only between atoms of type Mn1.

The atom or subIdx parameters are used to select specific bonds that are the same by symmetry or bond length.
For example

sw = spinw(); % default init
sw.addatom('r',[0 0 0],'S',1)
sw.addatom('r',[0.5, 0.5, 0.5],...
    'S',1, 'label', 'atom_2')
sw.addmatrix('label','J1','value', 1)   
sw.gencoupling('maxDistance',3); % generate bond list
sw.table('bond',[])

% idx    subidx        dl                  dr             length      matom1      idx1      matom2      idx2     
%     ___    ______    ___________    ____________________    ______    __________    ____    __________    ____ 
%      1       1       1    0    0     0.5    -0.5    -0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       2       0    1    0    -0.5     0.5    -0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       3       1    1    0     0.5     0.5    -0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       4       0    0    1    -0.5    -0.5     0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       5       1    0    1     0.5    -0.5     0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       6       0    1    1    -0.5     0.5     0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       7       1    1    1     0.5     0.5     0.5    2.598     {'atom_2'}     2      {'atom_1'}     1   
%      1       8       0    0    0     0.5     0.5     0.5    2.598     {'atom_1'}     1      {'atom_2'}     2   
%      2       1       1    0    0       1       0       0        3     {'atom_1'}     1      {'atom_1'}     1   
%      2       2       0    1    0       0       1       0        3     {'atom_1'}     1      {'atom_1'}     1   
%      2       3       0    0    1       0       0       1        3     {'atom_1'}     1      {'atom_1'}     1   
%      2       4       1    0    0       1       0       0        3     {'atom_2'}     2      {'atom_2'}     2   
%      2       5       0    1    0       0       1       0        3     {'atom_2'}     2      {'atom_2'}     2   
%      2       6       0    0    1       0       0       1        3     {'atom_2'}     2      {'atom_2'}     2   


% add bond only between atom_1 and atom_1 (bond 2 in obj.coupling.idx)
sw.addcoupling('mat', 'J1', 'bond', 2, ...
    'atom', {'atom_1', 'atom_1'})

% see which bonds are set
ibond = find(sw.coupling.mat_idx(1,:)); % [9, 10, 11]
% which corresponds to these rows in the above table
%      2       1       1    0    0       1       0       0        3     {'atom_1'}     1      {'atom_1'}     1   
%      2       2       0    1    0       0       1       0        3     {'atom_1'}     1      {'atom_1'}     1   
%      2       3       0    0    1       0       0       1        3     {'atom_1'}     1      {'atom_1'}     1   

It might be preferable to define your system with a spacegroup using the spgr parameter in genlattice - you might then be able to refer to the bond you want by subIdx?

Hope that helps!