Load OOMMF file to Matlab array

The function imports vector file (.omf/.ovf) from micromagnetic simulation output (OOMMF, mumax3 or Boris) into Matlab arrays

The function imports vector file archives from oommf [1], mumax3 [2], Boris [3] into Matlab arrays.

*with mumax3 was not tested, but should work with proper saving .ovf as a text. See comments about saving in OOMMF and Boris

The file is inspired by H. Corte and his function oommf2matlab.m

https://mathworks.com/matlabcentral/fileexchange/44187-oommf-vector-data-file-to-matlab-array

https://thebrickinthesky.wordpress.com/?s=OOMMF

ChatGPT [4] was used also.

Main modification: fileToRead is processed with fileread function, not line-by-line. It works much faster for large files (100+Mb)

OOMMF vector files must be writen with the output Specifications "text %g" instead of the default "binary 4" option. And the type of grid must be rectangular. In Boris use ns.saveovf2mag('text', output_file, bufferCommand=True)

Vector files will be imported into the object "data" which will have this fields (if exist in fileToRead):

datax: component x of vector on data file

datay: component y of vector on data file

dataz: component z of vector on data file

time: total simulation time

xmin: minimum x value

xnodes: number of nodes used along x

xmax: maximum x value

ymin: minimum y value

ynodes: number of nodes used along y

ymax: maximum y value

zmin: minimum z value

znodes: number of nodes used along z

zmax: maximum z value

positionx: x positions of vectors

positiony: y positions of vectors

positionz: z positions of vectors

The number of fields could be extended easily

Basic usage:

dataOMF = oommf2matlab("your_file_name.ovf")% it loads the data to variable dataOMF
% and you can use it as next
Mx = dataOMF.datax % returns array of Mx components
% replace 'datax' with the desired vector (see above)
% be careful - it returns 1D array other the nodes.
% to plot 2D data correctly refer to next example:

Example: Plot 2D images from all files in directory:

    %% read file names
    dir_name = './DirName/';
    file_extention = '*.ovf'; % .omf is also good
    f_n = dir([dir_name file_extention]);
    %% sort files by date
    [~,idx] = sort([f_n.datenum]);
    f_n = f_n(idx);
    fileNames = {f_n.name};    
    mult = 1e6; % switch dimentions to microns
    for ff = 1:length(fileNames)  
        dataOMF = omf2matlab([dir_name fileNames{ff}]);
        Xvector = mult* linspace(dataOMF.xmin, dataOMF.xmax, dataOMF.xnodes);
        Yvector = mult* linspace(dataOMF.ymin, dataOMF.ymax, dataOMF.ynodes);
        Magn_z = dataOMF.dataz
        imagesc(Xvector, Yvector, Magn_z');
        drawnow;
    end;    

References:

[1] OOMMF: Object Oriented MicroMagnetic Framework, NIST,

http://math.nist.gov/oommf/

[2] mumax3, a GPU-accelerated micromagnetic simulation

https://mumax.github.io/

[3] Boris Computational Spintronics,

Multi-physics magnetisation dynamics and spin transport simulations,

http://www.boris-spintronics.uk/

[4] ChatGPT https://chat.openai.com/

This function was written by N. Khokhlov

https://www.scopus.com/authid/detail.uri?authorId=57213491467

https://publons.com/researcher/2337219/nikolai-e-khokhlov/

https://scholar.google.com/citations?user=YKEZQLIAAAAJ&hl=en

https://www.researchgate.net/profile/N-Khokhlov