spinw.matparser method

parses parameter vector into matrices

Syntax

matparser(obj,Name,Value)

Description

matparser(obj,Name,Value) modifies the obj.matrix.mat matrix, assigning new values from a given parmeter vector.

Example

To assign a Dzyaloshinskii-Moriya vector to the 'DM' matrix, the following input would be sufficient:

cryst = spinw
cryst.addmatrix('label','DM','value',1)
P = [0.2 0.35 3.14]
M = {'DM' 'DM' 'DM'}
S = cat(3,[0 0 0;0 0 1;0 -1 0],[0 0 -1;0 0 0;1 0 0],[0 1 0;-1 0 0;0 0 0])
cryst.matparser('param',P,'mat',M,'selector',S)
cryst.matrix.mat

Output

    1.0000    3.1400   -0.3500
   -3.1400    1.0000    0.2000
    0.3500   -0.2000    1.0000

Input Arguments

obj: spinw object.

Name-Value Pair Arguments

'param': Input row vector P with nPar elements that contains the new values to be assignd to elements of obj.matrix.mat matrix.
'mat': Identifies which matrices to be changed according to their label or index. To select matrices with given labels use a cell of strings with $n_{par}$ elements, for example M = {'J1','J2'}. This will change the diagonal elements of matrices $J_1$ and $J_2$ to a given value that is provided in the param parameter vector. Alternatively the index of the matrices can be given in a vector, such as [1 2] (index runs according to the order of the previous creation of the matrices using spinw.addmatrix).
To assign parameter value only to a selected element of a $[3\times 3]$ matrix, a bracket notation can be used in any string, such as 'D(3,3)', in this case only the $(3,3)$ element of the $[3\times 3]$ matrix of 'D' will be modified, the other elements will be unchanged. To modify multiple elements of a matrix at once, use the option selector.
'selector': Matrix with dimensions of $[3\times 3\times n_{par}]$ . Each S(:,:,i) submatrix can contain $\pm 1$ and 0. Where S(:,:,i) contains 1, the corresponding matrix elements of spinw.matrix.mat(:,:,M(i)) will be changed to the value P(i)*S(:,:,i) where P(i) is the corresponding parameter value.
'init': Initialize the matrices of obj.matrix.mat with zeros for all selected labels before assigning parameter values. Default is false.

Output Arguments

The spinw object will contain the modified obj.matrix.mat field.