SpinW

https://spinw.org/
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### Install SpinW MATLAB Package

Source: https://spinw.org/IntroToSpinW

Steps to install the SpinW package in MATLAB. This involves downloading the release, unzipping it, and running the installation script. It also covers updating the package using `sw_update`.

```matlab
%% Install SpinW
% Download the latest release from https://www.github.com/spinw/spinw/releases/latest
% Unzip the archive into your preferred directory
% Open MATLAB and run 'install_spinw' from inside this directory
% Verify installation with: s = spinw;
```

```matlab
%% Update SpinW
% Use the self-update function to get the latest version
sw_update;
```

```matlab
%% Install SpinW as a MATLAB Add-on
% Search for SpinW in the MATLAB Add-on Explorer and install it.
```

--------------------------------

### Getting Help for SpinW Functions in MATLAB

Source: https://spinw.org/Tartu2019

To get help for functions starting with 'sw_*', use the 'help' command followed by the function name. For SpinW class methods, use 'help spinw.method_name'. Detailed documentation is also available online.

```matlab
help sw_*
help spinw.function_name
doc spinw/addatom
```

--------------------------------

### Create Ferromagnetic Kagome Lattice

Source: https://spinw.org/IntroToSpinW

Initializes a spinw object and defines a ferromagnetic Kagome lattice with specified lattice constants and space group. It adds magnetic atoms with spin information.

```matlab
FMkagome = spinw;
FMkagome.genlattice('lat_const',[6 6 5],'angled',[90 90 120],'spgr','P -3')
FMkagome.addatom('r', [1/2 0 0], 'S', 1, 'label','MCu1','color','r')
```

--------------------------------

### SpinW Installation and Verification (Matlab)

Source: https://spinw.org/NBI_2019

Instructions for installing the SpinW library in Matlab. It involves unzipping the archive, running an installation script, and verifying the installation by creating a spinw object.

```matlab
install_spinw
s = spinw;
```

--------------------------------

### Generate and Plot Spin Wave Data with dnd Object

Source: https://spinw.org/IntroToSpinW

Creates a dnd object for simulating spin wave data on a square lattice, fills it with calculated spin wave spectra using 'Sperp' component and magnetic form factors, and then plots a constant energy cut.

```matlab
d3dobj = d3d(sq.abc, [1 0 0 0], [-2,0.01,2], [0 1 0 0], [-2,0.01,2], [0 0 0 1], [0,0.1,10]);
d3dobj = disp2sqw_eval(d3dobj, @sq.horace, {'component', 'Sperp', 'useMex', false, 'formfact', true}, 0.3);

plot(cut(d3dobj, [], [], [3.8 4.2]))
```

--------------------------------

### Single Ion Anisotropy Setup in SpinW (MATLAB) - P0 Space Group

Source: https://spinw.org/SymmetryInSpinW

This example shows how to set up single-ion anisotropy using the P0 space group in SpinW with MATLAB. It details the process of creating a lattice, adding multiple magnetic atoms, generating couplings, defining an anisotropy matrix, and applying it to the system. A plot is generated to visualize the structure.

```matlab
cryst=spinw;
cryst.genlattice('lat_const',[8 8 6])
cryst.addatom('r',[1/4 1/4 0],'S',1)
cryst.addatom('r',[3/4 1/4 0],'S',1)
cryst.addatom('r',[1/4 3/4 0],'S',1)
cryst.addatom('r',[3/4 3/4 0],'S',1)
cryst.gencoupling
cryst.addmatrix('label','A','value',1-eye(3))
cryst.addaniso('A')

plot(cryst,'atomLegend',false)
```

--------------------------------

### spinw.addatom Method Documentation

Source: https://spinw.org/spinw_addatom

Detailed documentation for the spinw.addatom method, including syntax, description, examples, input arguments, and output.

```APIDOC
## spinw.addatom

### Description
Adds a new atom to the list of symmetry inequivalent sites together with its properties, such as position, spin quantum number, form factor, etc.

### Syntax
`addatom(obj, Name, Value)`

### Parameters
#### Input Arguments
- **obj** (spinw object) - The spinw object to which the atom will be added.

#### Name-Value Pair Arguments
- **r** (matrix) - Atomic positions stored in a matrix with dimensions of `[3 x n_atom]`.
- **label** (cell array of strings) - Names of the atoms in a cell for plotting and form factor calculations. Default is `atomi`, where `i` is the atom index.
- **S** (row vector) - Spin quantum number stored in a row vector with `n_atom` elements. For non-magnetic atoms, set S to zero. If not given, the spin quantum number is guessed from the label.
- **color** (matrix or string or cell array) - RGB color of the atoms for plotting stored in a matrix with dimensions of `[3 x n_atom]`, where each column describes an RGB color. Values are between 0 and 255. Can also be a color name string or a cell array of color names for multiple atoms.
- **ox** (double) - Oxidation number. Default is 0.
- **occ** (double) - Occupancy. Default is 1.
- **formfact** (row vector or string) - Neutron scattering form factor. Can be a row vector with 9 numbers or a string label from magion.dat.
- **formfactn** (row vector or string) - Same as `formfact`.
- **formfactx** (row vector or string) - X-ray scattering form factor. Can be a row vector with 9 numbers or a string label from xrayion.dat.
- **Z** (integer) - Atomic number. Default is 113 (Unobtanium).
- **A** (integer) - Atomic mass. Default is -1 for the natural mixture of isotopes.
- **bn** (double) - Neutron scattering length. Not implemented yet.
- **bx** (double) - X-ray scattering length.
- **biso** (double) - Isotropic displacement factors in units of Å^2.
- **update** (logical) - If `true`, existing atoms with the same label and position will be updated. Default is `true`.

### Output Arguments
Modifies the `spinw.unit_cell` property of the `obj` spinw object.

### Example
```matlab
crystal = spinw;
crystal.genlattice('lat_const',[4 3 3])
crystal.addatom('r',[0 1/2; 0 0; 0 0],'S',[1 0],'color',{'red' 'blue'})
crystal.plot
```

### See Also
spinw.genlattice | spinw.addmatrix | swplot.color | sw_mff | sw_cff
```

--------------------------------

### Accessing Function Help in SpinW (Matlab)

Source: https://spinw.org/NBI_2019

Explains how to access help documentation for SpinW functions in Matlab. Specifically, it shows how to use the `help` command for functions starting with `sw_*`.

```matlab
help sw_*
```

--------------------------------

### Open Help Files and Utilities in SpinW

Source: https://spinw.org/tutorials/30tutorial

This snippet demonstrates how to open help files, locate the SpinW root directory, and edit configuration files using MATLAB commands. It also shows how to view and manage SpinW preferences.

```matlab
help swfiles

% To find the location of the spinw library use
sw_rootdir

% To open any of the functions in the Matlab editor, use
edit spinw.plot

% To look at any of the spinw object properties, double click on the
% "Workspace" view on the name of the object. Also the data files
% (symmetry.dat, atom.dat, color.dat, magion.dat) can be easily edited, for
% example

edit symmetry.dat

% Some settings are ekpt during the active Matlab session, these can be
% set/get using the swpref.setpref and swpref.getpref commands. To change
% the default values, it can be defined in the startup.m file. To get all
% current value use

swpref
```

--------------------------------

### Add SpinW to Matlab Path Permanently

Source: https://spinw.org/installation

This snippet demonstrates how to add the SpinW installation directory and all its subdirectories to the permanent Matlab path by modifying the `startup.m` file. This ensures that SpinW functions are accessible every time Matlab is started. Replace `YOUR_PATH` with the actual directory where SpinW is unzipped.

```matlab
addpath(genpath([YOUR_PATH '/spinw/spinw_2-0beta_rev195']))
```

--------------------------------

### Update SpinW Installation

Source: https://spinw.org/installation

This command is used to automatically check for, download, and install the latest version of SpinW. It also updates the Matlab search path to include the new files. After execution, it's recommended to clear Matlab's class cache.

```matlab
sw_update()
```

--------------------------------

### Compiling SpinW Mex Files

Source: https://spinw.org/SpinWAndHorace

Provides instructions for compiling SpinW's mex files, which are C libraries for speeding up calculations. This requires a Matlab-compatible compiler (e.g., Visual Studio, gcc, XCode) and involves running `mex -setup` followed by `sw_mex` or `sw_mex('test', true)` to compile and test.

```bash
mex -setup
```

```bash
sw_mex
```

```bash
sw_mex('test', true)
```

--------------------------------

### Define and Fit S(q,ω) Models in Horace using SpinW

Source: https://spinw.org/SpinWAndHorace

This example shows how to use SpinW's `horace_sqw` function within Horace's `multifit_sqw` for fitting experimental data. It details setting up the model, defining parameters to be varied (including matrix elements), and specifying simulation options like resolution functions.

```matlab
J = 1.2;
K = 0.1;
tri = sw_model('triAF', J);
tri.addmatrix('label', 'K', 'value', diag([0 0 K]));
tri.addaniso('K');

fwhm = 0.75;
scalefactor = 1;
ws = cut_sqw(sqw_file, [0.05], [-0.1, 0.1], [-0.1, 0.1], [0.5]);
fitobj = multifit_sqw(ws);
fitobj.set_fun(@tri.horace_sqw);
fitobj.set_pin({[J K fwhm scalefactor], 'mat', {'J_1', 'K(3,3)'}, ...
    'hermit', false, 'useFast', true, 'formfact', true});
ws_sim = fitobj.simulate();
[ws_fit, fit_dat] = fitobj.fit()
```

--------------------------------

### Calculate and Plot Powder Spectrum

Source: https://spinw.org/IntroToSpinW

Calculates the powder spectrum by averaging over random orientations and plots it in two ways: raw and convoluted with a Gaussian to simulate experimental broadening.

```matlab
fmkPow = FMkagome.powspec(linspace(0,2.5,100),'Evect',linspace(0,7,250),'nRand',1000,'hermit',false);
figure
subplot(2,1,1)
sw_plotspec(fmkPow,'colorbar',true,'axLim',[0 0.05])
```

--------------------------------

### spinw.optmagsteep Method Documentation

Source: https://spinw.org/spinw_optmagsteep

Details on the syntax, description, input arguments, name-value pair arguments, output arguments, and related functions for the spinw.optmagsteep method.

```APIDOC
## spinw.optmagsteep

### Description
`optm = optmagsteep(obj,Name,Value)` determines the lowest energy magnetic configuration within a given magnetic supercell and previously fixed propagation (and normal) vector. It iteratively rotates each spin towards the local magnetic field, achieving a local energy minimum. This method often finds the global energy minimum, especially for small magnetic cells and non-frustrated structures, and is comparable to thermal quenching from the paramagnetic state.

### Method
```matlab
optm = optmagsteep(obj,Name,Value)
```

### Input Arguments

*   `obj` (spinw object): The spinw object containing the magnetic structure.

### Name-Value Pair Arguments

*   `'nRun'` (integer): Number of iterations. Default is 100. Each spin is quenched `nRun` times or until convergence.
*   `'boundary'` (string): Boundary conditions for the magnetic cell. Allowed values: `'free'` (omits interactions between extended unit cells) or `'per'` (retains interactions). Default is `{'per' 'per' 'per'}`.
*   `'nExt'` (integer): Size of the magnetic cell in number of crystal unit cells. Default is `obj.mag_str.nExt`.
*   `'fSub'` (function handle): Function to define non-interacting sublattices for parallelization. It should have the header `cGraph = fSub(conn,nExt)`.
*   `'subLat'` (vector): Vector assigning magnetic moments to non-interacting sublattices. If undefined, the `fSub` function is used.
*   `'random'` (boolean): If `true`, uses random initial spin orientations (paramagnetic state). If the initial spin configuration is undefined, it will always be random. Default is `false`.
*   `'TolX'` (double): Minimum change of the magnetic moment required for convergence.
*   `'saveAll'` (boolean): If `true`, saves moment directions for every loop. Default is `false`.
*   `'Hmin'` (double): Minimum field value on a spin required to move the spin. If the molecular field absolute value is below this, the spin will not be turned. Default is 0.
*   `'plot'` (boolean): If `true`, plots the magnetic structure in real time. Default is `false`.
*   `'pause'` (double): Time in seconds to pause after each optimization loop for slower plot movies. Default is 0.
*   `'fid'` (integer): Defines text output generation. Default is determined by the `fid` preference in `swpref`. Possible values: `0` (no output), `1` (MATLAB Command Window), or a file ID from `fopen`.

### Output Arguments

*   `optm` (struct): A struct containing the optimization results:
    *   `obj` (spinw object): The spinw object with the optimized magnetic structure.
    *   `M` (3D array): Magnetic moment directions. Dimensions: `[3 x n_magExt]` or `[3 x n_magExt x n_loop]` if `saveAll` is `true`.
    *   `dM` (vector): The average change in the magnetic moment vector over all moments in the last loop.
    *   `e` (double): Energy per spin in the optimized structure.
    *   `param` (struct): Input parameters used for the optimization.
    *   `nRun` (integer): Number of loops executed.
    *   `datestart` (datetime): Starting time of the function execution.
    *   `dateend` (datetime): Ending time of the function execution.
    *   `title` (string): Title of the simulation, if provided.

### See Also

*   `spinw`
*   `spinw.anneal`
*   `sw_fsub`
*   `sw_fstat`
```

--------------------------------

### swpref.import Method

Source: https://spinw.org/swpref_import

Imports preferences from a JSON file into the SpinW application. It can load from the default user's home folder or a specified location.

```APIDOC
## swpref.import Method

### Description
Loads preferences from a JSON file. If no location is specified, it defaults to `swprefs.json` in the user's home folder. The loaded preferences are then applied, and a new preference object is returned.

### Method
`obj = import(obj)`
`obj = import(obj,location)`

### Parameters
#### Path Parameters
* **obj** (object) - Required - The preference object to be updated.
* **location** (string) - Optional - The file path to the preferences JSON file.

### Request Example
```json
{
  "obj": {},
  "location": "/path/to/your/prefs.json"
}
```

### Response
#### Success Response (200)
* **obj** (object) - The updated preference object.

#### Response Example
```json
{
  "obj": {
    "preference1": "value1",
    "preference2": "value2"
  }
}
```
```

--------------------------------

### Set Ferromagnetic Magnetic Structure

Source: https://spinw.org/IntroToSpinW

Sets a ferromagnetic magnetic structure where all spins are parallel along the y-axis. It uses the 'helical' mode of `genmagstr` with k=[0 0 0] to achieve this.

```matlab
FMkagome.genmagstr('mode', 'helical', 'k', [0 0 0], 'n', [0 1 0], 'S', [0 1 0])
disp('Magnetic structure:')
FMkagome.table('mag')
FMkagome.energy
plot(FMkagome,'range',[2 2 1])
```

--------------------------------

### Define Nearest Neighbor Couplings

Source: https://spinw.org/IntroToSpinW

Generates the nearest neighbor ferromagnetic couplings for the Kagome lattice. It uses `gencoupling` to identify symmetry-equivalent bonds up to a specified distance and displays bond information.

```matlab
FMkagome.gencoupling('maxDistance',4)
disp('Bonds (length in Angstrom):')
FMkagome.table('bond',[])
```

--------------------------------

### Defining Matrix Parameters with 'mat' and 'selector' in SpinW

Source: https://spinw.org/SpinWAndHorace

Demonstrates how to define parameters for spin wave calculations using the 'mat' argument in SpinW. It shows how to add matrices, couple them, and use a 'selector' matrix for more complex parameter definitions. This is useful for specifying which elements of a matrix correspond to a given parameter.

```matlab
Dvec = [0.1 0.2 0.3];
swobj.addmatrix('label', 'DM', 'value', Dvec);
swobj.addcoupling('mat', 'DM', 'bond', 1);

sel(:,:,1) = [0 0 0; 0 0 1; 0 -1 0];    % Dx
sel(:,:,2) = [0 0 1; 0 0 0; -1 0 0];    % Dy
sel(:,:,3) = [0 1 0; -1 0 0; 0 0 0];    % Dz

fitobj.set_fun(@swobj.horace_sqw);
fitobj.set_pin({Dvec, 'mat', {'DM', 'DM', 'DM'},
    'selector', sel, 'hermit', false})
fitobj.fit()
```

--------------------------------

### Enabling Mex Files in SpinW for Faster Calculations

Source: https://spinw.org/SpinWAndHorace

Shows how to enable the use of compiled mex files in SpinW to accelerate spin wave calculations. This involves setting a preference using `swpref.setpref('usemex', true)`. If mex files are not compatible, an error will occur.

```matlab
swpref.setpref('usemex',true)
```

--------------------------------

### Convolute Spin Wave Spectra with Energy Resolution

Source: https://spinw.org/IntroToSpinW

Applies an energy resolution convolution to the previously calculated spin wave spectra using the `sw_instrument` function with a specified energy broadening `dE`.

```matlab
spec = sw_instrument(spec,'dE',0.5);
```

--------------------------------

### Plot Density of Magnon States

Source: https://spinw.org/IntroToSpinW

Calculates and plots the density of magnon states by sampling random points in the Brillouin Zone, followed by Gaussian convolution for smoothing. It uses the 'Sxx+Syy+Szz' component for the calculation.

```matlab
nQ = 1E5;
Q = rand(3, nQ);

spec = FMkagome.spinwave(Q, 'hermit', false);
spec = sw_egrid(spec, 'component', 'Sxx+Syy+Szz');
spec = sw_instrument(spec, 'dE', 0.1);
I = sum(spec.swConv, 2);
E = spec.Evect(2:end);
```

--------------------------------

### SpinW Model Evaluation and Fitting Setup

Source: https://spinw.org/Ispra2019

Sets up a multifit object using a 2D cut dataset, defines the SpinW model function with parameters and options, and enables the use of mex files for faster computation. It then times a single simulation iteration.

```matlab
idx = 5;            % EIs: [25 35 50 70 140], index 5 == 140meV 
fwhm = ei(idx)/30;  % Typical resolution ~ 3% of Ei  

kk = multifit_sqw(d2d(ws_sub(idx)));
kk = kk.set_fun (@pcsmo.horace_sqw, {[JF1 JA JF2 JF3 Jperp D fwhm] cpars{:}}); 
kk = kk.set_free ([1, 1, 1, 1, 1, 1, 1]); 
kk = kk.set_options ('list',2);  

swpref.setpref('usemex',true);  
% Time a single iteration 
tic 
wsim = kk.simulate; 
t_spinw_single = toc;
```

--------------------------------

### Calculate and Plot Spin Wave Dispersion for Kagome Lattice

Source: https://spinw.org/IntroToSpinW

Calculates the spin wave dispersion for the ferromagnetic Kagome lattice along specified high-symmetry directions and plots the spectrum with energy grid.

```matlab
fmkSpec = FMkagome.spinwave({[-1/2 0 0] [0 0 0] [1/2 1/2 0] 100},'hermit',false);
fmkSpec = sw_neutron(fmkSpec);
fmkSpec = sw_egrid(fmkSpec, 'Evect',linspace(0,6.5,100),'component','Sperp');
figure
sw_plotspec(fmkSpec,'mode',1,'colorbar',false,'axLim',[0 8])
```

--------------------------------

### Import swpref Object from File (MATLAB)

Source: https://spinw.org/swpref

Demonstrates loading swpref preferences from a file using the swpref.import method.

```matlab
pref = swpref
filename = 'my_preferences.mat';
swpref.import(pref, filename)
% Alternatively:
% pref.import(filename)
```

--------------------------------

### Clear Matlab Class Cache

Source: https://spinw.org/installation

This command clears the cache of user-defined classes in Matlab. It is often necessary after updating packages or making changes to class definitions to ensure that Matlab recognizes the latest versions of the classes.

```matlab
clear classes
```

--------------------------------

### Compare Spin Wave Intensities Along Different Directions

Source: https://spinw.org/IntroToSpinW

Compares the spin wave intensities along two different directions in reciprocal space. It generates plots for both directions, allowing for visual comparison of intensity profiles.

```matlab
Fact = 1;
amark o
acolor r
plot(cut(Fact*d3dobj, [-0.1 0.1], [], [0 5]))
acolor k
pm(cut(d3dobj, [], [-0.1 0.1], [0 5]))
```

--------------------------------

### Powder Averaging of Spin Wave Spectra

Source: https://spinw.org/IntroToSpinW

Generates a powder-averaged spin wave spectrum. This involves creating a lattice, calculating the powder spectrum with specified energy and momentum ranges, applying an energy resolution convolution, and plotting the result.

```matlab
sq.genlattice('lat_const', [6 6 9]);
spec = sq.powspec(linspace(0, 2, 101), 'Evect', linspace(0, 5, 501), 'nRand', 3e3, 'useMex', false, 'formfact', true);
spec = sw_instrument(spec, 'dE', 0.2, 'Ei', 8, 'thetaMin', 5);
sw_plotspec(spec, 'mode', 'color', 'dE', 0.2)
caxis([0 0.2])
```

--------------------------------

### Display Magnetic Structure Table

Source: https://spinw.org/tutorials/08tutorial

This snippet displays the generated magnetic structure in a tabular format. It shows details for each magnetic site, including atomic index, spin vector, real and imaginary components of the magnetic form factor, position, and k-vector.

```matlab
Magnetic structure:

ans =

  27×8 table

    num    matom     idx    S            realFhat                     imagFhat                    pos                        kvect              
    ___    ______    ___    _    ________________________    __________________________    _________________    ________________________________

     1     'MCu1'     1     1    -0.5     0.866         0    -0.866      -0.5         0    0.5      0      0    -0.33333    -0.33333           0
     2     'MCu1'     2     1    -0.5     0.866         0    -0.866      -0.5         0      0    0.5      0    -0.33333    -0.33333           0
     3     'MCu1'     3     1    -0.5    -0.866         0     0.866      -0.5         0    0.5    0.5      0    -0.33333    -0.33333           0
     4     'MCu1'     1     1       1         0         0         0         1         0    1.5      0      0    -0.33333    -0.33333           0
     5     'MCu1'     2     1       1         0         0         0         1         0      1    0.5      0    -0.33333    -0.33333           0
     6     'MCu1'     3     1    -0.5     0.866         0    -0.866      -0.5         0    1.5    0.5      0    -0.33333    -0.33333           0
     7     'MCu1'     1     1    -0.5    -0.866         0     0.866      -0.5         0    2.5      0      0    -0.33333    -0.33333           0
     8     'MCu1'     2     1    -0.5    -0.866         0     0.866      -0.5         0      2    0.5      0    -0.33333    -0.33333           0
     9     'MCu1'     3     1       1         0         0         0         1         0    2.5    0.5      0    -0.33333    -0.33333           0
    10     'MCu1'     1     1       1         0         0         0         1         0    0.5      1      0    -0.33333    -0.33333           0
    11     'MCu1'     2     1       1         0         0         0         1         0      0    1.5      0    -0.33333    -0.33333           0
    12     'MCu1'     3     1    -0.5     0.866         0    -0.866      -0.5         0    0.5    1.5      0    -0.33333    -0.33333           0
    13     'MCu1'     1     1    -0.5    -0.866         0     0.866      -0.5         0    1.5      1      0    -0.33333    -0.33333           0
    14     'MCu1'     2     1    -0.5    -0.866         0     0.866      -0.5         0      1    1.5      0    -0.33333    -0.33333           0
    15     'MCu1'     3     1       1         0         0         0         1         0    1.5    1.5      0    -0.33333    -0.33333           0
    16     'MCu1'     1     1    -0.5     0.866         0    -0.866      -0.5         0    2.5      1      0    -0.33333    -0.33333           0
    17     'MCu1'     2     1    -0.5     0.866         0    -0.866      -0.5         0      2    1.5      0    -0.33333    -0.33333           0
    18     'MCu1'     3     1    -0.5    -0.866         0     0.866      -0.5         0    2.5    1.5      0    -0.33333    -0.33333           0
    19     'MCu1'     1     1    -0.5    -0.866         0     0.866      -0.5         0    0.5      2      0    -0.33333    -0.33333           0
    20     'MCu1'     2     1    -0.5    -0.866         0     0.866      -0.5         0      0    2.5      0    -0.33333    -0.33333           0
    21     'MCu1'     3     1       1         0         0         0         1         0    0.5    2.5      0    -0.33333    -0.33333           0
    22     'MCu1'     1     1    -0.5     0.866         0    -0.866      -0.5         0    1.5      2      0    -0.33333    -0.33333           0
    23     'MCu1'     2     1    -0.5     0.866         0    -0.866      -0.5         0      1    2.5      0    -0.33333    -0.33333           0
    24     'MCu1'     3     1    -0.5    -0.866         0     0.866      -0.5         0    1.5    2.5      0    -0.33333    -0.33333           0
    25     'MCu1'     1     1       1         0         0         0         1         0    2.5      2      0    -0.33333    -0.33333           0
    26     'MCu1'     2     1       1         0         0         0         1         0      2    2.5      0    -0.33333    -0.33333           0
    27     'MCu1'     3     1    -0.5     0.866         0    -0.866      -0.5         0    2.5    2.5      0    -0.33333    -0.33333           0
```

--------------------------------

### Generate Random Cylinders with swplot.cylinder (MATLAB)

Source: https://spinw.org/swplot_cylinder

This example demonstrates how to generate 100 random cylinders within a specified cube using the swplot.cylinder function. It utilizes random start and end points, a defined radius, and specifies the number of patch faces and closure.

```matlab
swplot.figure
N = 100;
swplot.cylinder(2*rand(3,N)-1,2*rand(3,N)-1,0.1,100,true)
swplot.zoom(30)
```

--------------------------------

### Calculate Spin Wave Dispersion Along a Defined Path

Source: https://spinw.org/IntroToSpinW

Calculates the spin wave dispersion along a specified path in reciprocal space connecting high-symmetry points (G, X, M). The path is defined by a series of points and the number of steps.

```matlab
G = [0     0 0];
X = [1/2   0 0];
M = [1/2 1/2 0];

spec = sq.spinwave({G X M G 301});
```

--------------------------------

### Set up AFM Hamiltonian in SpinW

Source: https://spinw.org/tutorials/08tutorial

This code sets up an antiferromagnetic (AFM) first neighbor interaction in the SpinW model. It adds a matrix labeled 'J1' with a value of 1.00 and assigns this matrix to the first neighbor bonds using spinw.addmatrix and spinw.addcoupling. The lattice is then plotted again to visualize the Hamiltonian.

```matlab
AF33kagome.addmatrix('label','J1','value',1.00,'color','g')
AF33kagome.addcoupling('mat','J1','bond',1)
plot(AF33kagome,'range',[2 2 1/2],'cellMode','inside')
```

--------------------------------

### Create Square Lattice Heisenberg Antiferromagnet Model

Source: https://spinw.org/IntroToSpinW

Defines a square lattice Heisenberg antiferromagnet model with specified spin and exchange parameters using `sw_model`. It also adds an atom with its magnetic form factor. The resulting model can be visualized.

```matlab
sq = sw_model('squareAF', 1);
sq.addatom('label', 'atom_1', 'r', [0 0 0], 'formfactn', 'MCu2+', 'S', 1/2)
plot(sq)
```

--------------------------------

### Determine Propagation Vector of Cycloid in BiFeO3 using SpinW

Source: https://spinw.org/magneticStructurePresentation

A worked example demonstrating the use of optmagk in SpinW to determine the propagation vector 'k' of the spin cycloid in multiferroic BiFeO3. The script allows exploration of how DM and Heisenberg exchange interactions influence 'k'.

```matlab
# Download the script here: `bifeo3.m`
# BiFeO3 cycloid 
# Tutorial 1: Propagation vector of cycloid in BiFeO3
# This tutorial uses `optmagk` to determine the propagation vector kk of the spin cycloid in multiferroic BiFeO3
```

--------------------------------

### DM Interaction Setup in SpinW (MATLAB)

Source: https://spinw.org/SymmetryInSpinW

This snippet demonstrates how to set up a crystal structure with DM interaction using the P0 space group in SpinW. It involves generating a lattice, adding atoms with specified positions and spins, defining coupling matrices, and applying DM interactions. The output is a plot visualizing the magnetic structure.

```matlab
cryst=spinw;
cryst.genlattice('lat_const',[8 8 6])
cryst.addatom('r',[1/4 1/4 0],'S',1);
cryst.addatom('r',[3/4 1/4 0],'S',1);
cryst.addatom('r',[1/4 3/4 0],'S',1);
cryst.addatom('r',[3/4 3/4 0],'S',1);
cryst.gencoupling
cryst.addmatrix('label','D','value',[1 -1 0])
cryst.addcoupling('mat','D','bond',1,'subIdx',[3 5 7:8])

plot(cryst,'range',[1 1 1/2],'atomLegend',false)
```

--------------------------------

### Configure SpinW Model Parameters (MATLAB)

Source: https://spinw.org/SpinWAndHorace

This snippet shows how to set up specific parameters for a SpinW model, including coordinate transformations and general options like matrix definitions, hermeticity, speed optimizations, and resolution functions. It's used for preparing a model for evaluation or fitting.

```MATLAB
cpars = {'coordtrans', diag([2 2 1 1])}
                        
cpars = {cpars{:}, 'mat', {'JF1', 'JA', 'JF2', 'JF3', 'Jperp', 'D(3,3)'}, ...
    'hermit', false, 'optmem', 0, 'useFast', true, 'formfact', true, ...
    'resfun', 'gauss'};
                        
```

--------------------------------

### SpinW Object Creation

Source: https://spinw.org/spinw_spinw

This section details the different ways to instantiate a SpinW object, each serving a specific purpose from creating an empty object to importing data or cloning existing objects.

```APIDOC
## SpinW Object Creation and Initialization

### Description
The `spinw` method provides multiple syntaxes for creating and initializing SpinW objects, allowing for flexibility in how you start working with spin wave data.

### Method
Various constructors are available depending on the input arguments.

### Endpoint
`spinw` (method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```json
{
  "example": "obj = spinw()"
}
```

### Response
#### Success Response (200)
- **obj** (SpinW object) - A SpinW object initialized according to the provided syntax.

#### Response Example
```json
{
  "example": "obj = spinw() // Creates an empty SpinW object"
}
```

### Detailed Syntaxes:

1.  **`obj = spinw`**
    *   **Description**: Creates an empty SpinW object with default values.
    *   **Request Example**: `obj = spinw`

2.  **`obj = spinw(struct)`**
    *   **Description**: Creates a SpinW object from a structure (`struct`) which must have fields compatible with the SpinW property structure.
    *   **Parameters**: `struct` (struct) - A structure containing SpinW properties.
    *   **Request Example**: `obj = spinw(my_structure)`

3.  **`obj = spinw(hFigure)`**
    *   **Description**: Clones a SpinW object from an existing swplot figure (`hFigure`) or spectral plot figure.
    *   **Parameters**: `hFigure` (figure handle) - Handle to a SpinW or spectral plot figure.
    *   **Request Example**: `obj = spinw(gcf)`

4.  **`obj = spinw(fName)`**
    *   **Description**: Imports data from a file specified by `fName`. SpinW can import crystal or magnetic structure data from `.cif` or `.fts` files, accessible from local paths or web addresses.
    *   **Parameters**: `fName` (string) - The filename or URL of the data file.
    *   **Request Example**: `obj = spinw('https://example.com/my_structure.cif')`

5.  **`obj = spinw(obj)`**
    *   **Description**: Checks the input SpinW object (`obj`) for internal consistency.
    *   **Parameters**: `obj` (SpinW object) - The SpinW object to check.
    *   **Request Example**: `obj = spinw(existing_spinw_object)`

```

--------------------------------

### Verifying SpinW Installation via MATLAB Add-on

Source: https://spinw.org/Tartu2019

After installing SpinW as a MATLAB add-on from Mathworks, users can verify the installation by creating a SpinW object. This confirms that the package has been correctly integrated into the MATLAB environment.

```matlab
s = spinw;
```

--------------------------------

### SpinW Model Initialization - Coordinate Transformation

Source: https://spinw.org/Ispra2019

Sets up coordinate transformation parameters for SpinW, specifically multiplying Qh and Qk by 2. This is necessary when the structural unit cell used in SpinW differs from that in Horace.

```matlab
cpars = {'coordtrans', diag([2 2 1 1])}
```

--------------------------------

### Get Anisotropy Matrix Elements in C4 Point Group

Source: https://spinw.org/spinw_getmatrix

This example demonstrates how to use `getmatrix` to find the allowed anisotropy matrix elements for an atom within the C4 point group. The code first sets up a crystal structure with C4 symmetry, adds an atom, assigns a matrix, generates couplings, adds anisotropy, and then calls `getmatrix` to retrieve the symmetry-allowed elements. The output shows the structure of the allowed symmetric matrix.

```matlab
cryst = spinw
cryst.genlattice('sym','P 4')
cryst.addatom('r',[0 0 0],'label','MCu2')
cryst.addmatrix('label','A','value',1)
cryst.gencoupling
cryst.addaniso('A')
cryst.getmatrix('mat','A')
```

--------------------------------

### Example: Helical Magnetic Structure

Source: https://spinw.org/NBI_2019

Example of generating a helical magnetic structure for a Cr3 material. This involves setting up the lattice, adding atoms, and then calling genmagstr with the 'helical' mode.

```matlab
tri = spinw;
tri.genlattice('lat_const', [4 4 6], 'angled', [90 90 120]);
tri.addatom('r', [0 0 0], 'S', 2, 'label', 'MCr3', 'color', 'gold');
tri.genmagstr('mode', 'helical', 'S', [1; 0; 0], 'n', [0 0 1], 'k', [1/3 1/3 0])
```

--------------------------------

### Perform SpinW Model Simulation and Fit (MATLAB)

Source: https://spinw.org/SpinWAndHorace

This code performs a simulation using a configured SpinW model and a multifit object. It selects a specific energy dataset, sets up a multifit object using a dnd object for efficiency, enables mex files for speed, and times a single simulation iteration. This is crucial for evaluating model performance against experimental data.

```MATLAB
idx = 5;            % EIs: [25 35 50 70 140], index 5 == 140meV 
fwhm = ei(idx)/30;  % Typical resolution ~ 3% of Ei  

kk = multifit_sqw(d2d(ws_sub(idx)));
kk = kk.set_fun (@pcsmo.horace_sqw, {[JF1 JA JF2 JF3 Jperp D fwhm] cpars{:}}); 
kk = kk.set_free ([1, 1, 1, 1, 1, 1, 1]); 
kk = kk.set_options ('list',2);

swpref.setpref('usemex',true);  
% Time a single iteration 
tic 
wsim = kk.simulate; 
t_spinw_single = toc;
                    
```

--------------------------------

### Example: Random Magnetic Structure

Source: https://spinw.org/NBI_2019

Example of generating a random magnetic structure for a Cr3 material. This involves setting up the lattice, adding an atom, and calling genmagstr with the 'random' mode and specified 'nExt'.

```matlab
fct = spinw;
fct.genlattice('lat_const', [4 4 6], 'angled', [90 90 90]);
fct.addatom('r', [0.5 0.5 0], 'S', 2, 'label', 'MCr3', 'color', 'gold');
fct.genmagstr('mode', 'random', 'nExt', [2 2 1])
```

--------------------------------

### Example: Fourier Magnetic Structure

Source: https://spinw.org/NBI_2019

Example of generating a magnetic structure using Fourier components for a Cr3 material. This demonstrates setting up the lattice, adding atoms, and using the 'fourier' mode in genmagstr.

```matlab
mmod = spinw;
mmod.genlattice('lat_const', [4 4 6], 'angled', [90 90 90]);
mmod.addatom('r', [0.5 0.5 0.5], 'S', 2, 'label', 'MCr3', 'color', 'gold');
mmod.genmagstr('mode', 'fourier', 'S', [0; 1; 0], 'k', [0.07 0 0])
```

--------------------------------

### Calculate Powder Spectrum

Source: https://spinw.org/tutorials/08tutorial

Calculates the powder spectrum using a small magnetic cell for faster computation. The speed is dependent on the number of Q points and random orientations, with minimal dependence on energy bin size.

```matlab
kag33Pow = AF33kagome.powspec(linspace(0,2.5,100),'Evect',linspace(0,3,500),
    'hermit',false,'nRand',1e2);
figure
sw_plotspec(kag33Pow,'axLim',[0 0.2],'dE',0.05)
```
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