fits spin wave spectra to experimental spectral data fitsp = FITSPEC(obj, 'Option1', Value1, ...) Options: epsilon Small number that controls wether the magnetic structure is incommensurate or commensurate, default value is 1e-5. func Function to change the Hamiltonian in obj, it has the following header: obj = @func(obj, x); datapath Path to the file that stores the experimental data. For the input data format see <a href="matlab:doc sw_readspec">sw_readspec</a>. Evect Vector, defines the energy binning of the calculated dispersion. Larger binning steps solve the issue of fitting unresolved modes. Size is [1 nE]. xmin Minimum limit of the optimisation parameters, optional. xmax Maximum limit of the optimisation parameters, optional. x0 Starting value of the optimisation parameters. If empty or undefined, then random values are used. nRun Number of consecutive fitting runs, each result is saved in the output fitsp.x and R arrays. If the Hamiltonian given by the random x parameters is incompatible with the ground state, those x values will be skipped and new random x values will be generated. Default is 1. nMax Maximum number of runs, including the ones that produce error (due to incompatible ground state). Default is 1000. hermit Method for matrix diagonalization: true J.H.P. Colpa, Physica 93A (1978) 327, false R.M. White, PR 139 (1965) A450. Colpa: the grand dynamical matrix is converted into another Hermitian matrix, that will give the real eigenvalues. White: the non-Hermitian g*H matrix will be diagonalised, that is not the elegant method. Advise: Always use Colpa's method that is faster, except when small imaginary eigenvalues are expected. In this case only White's method work. Default is true. Parameters for visualizing the fit results: plot If true, the measured dispersion is plotted together with the fit. Default is true. wFact Weigth of the spin wave enenergies, plotted as the width of the data points (vertical lines). iFact Factor of the plotted simulated spin wave intensity (red ellipsoids). lShift Vertical shift of the Q point labels on the plot. Optimisation options: tolx Minimum change of x when convergence reached, default value is 1e-4. tolfun Minimum change of the R value when convergence reached, default value is 1e-5. maxfunevals Maximum number of function evaluations, default value is 1e7. Output: Output fitsp is struct type with the following fields: obj Copy of the input sw class object, with the best fitted Hamiltonian. x Final values of the fitted parameters, dimensions are [nRun nPar]. The rows of x are sorted according to increasing R values. R R-value, goodness of the fit, dimensions are [nRun 1], sorted in increasing order. exitflag Exit flag of the fminsearch command. output Output of the fminsearch command. Any option used by SW.SPINWAVE function are also accepted. See also SW.SPINWAVE, SW_EGRID, SW_NEUTRON, SW_READSPEC, FMINSEARCH.

- plot plots crystal structure, magnetic structure, anisotropy and couplings
- struct extracts all public properties of sw object into a struct

Generated on Mon 26-Nov-2018 15:08:42 by