sqw_spinwave: build a SpinWave model (S. Petit/LLB)
MODEL CREATION
Performs a SPINWAVE calculation using S. Petit/LLB code. The input file can be:
* a spinwave input file, such as MnFe4Si3.txt (in Data)
* 'defaults' will use an example.
* a CIF/CFL/ShelX file. In this case only the structure is imported, and
it is REQUIRED to edit the generated model in particular
the moment type 'NOM' and couplings J1,D1 (J2,D2) must be set.
* a Crystallography.net ID then specify 'cod: ID' as file name,
e.g. 'cod: 1006141'
* a chemical formula, then specify 'cod: formula' in Hill notation,
e.g. 'cod: La Mn O3'
* 'gui' to get a dialogue window and enter a COD ID or formula.
The input file may contain tokens to identify variable model patrameters.
The tokens format can be '$par' or '($par=val)' to specify default values.
The access to COD requires a valid network connection.
You can check for SPINWAVE installation with: sqw_spinwave check
You can compile SPINWAVE with: sqw_spinwave compile
The SPINWAVE model is built as S(q,w) 4D, or 2D when 'action' contains 'powder'.
The 4D model does not support the 'powder' iFunc_Sqw4D method, so the spinwave
should instead use sqw_spinwave('file','powder')
model = sqw_spinwave(file)
input:
file: file name of a SpinWave input file or CIF/CFL/ShelX or COD ID
action: string that may contain 'powder' (to create a 2D integrated powder model)
and 'edit' to edit the SpinWave input file.
output:
model: SpinWave model [iFunc_Sqw4D or iFunc_Sqw2D (powder)].
The model parameters are set as '$par' symbols in the spinwave template, which
you can edit with sqw_spinwave(mode, 'edit'). Remember to SAVE before closing.
MODEL EVALUATION
You may edit the SPINWAVE input file anytime with: sqw_spinwave(model, 'edit')
Remember to SAVE before closing.
Powder 2D case: Once created, the model is used as:
value = model(p, q, w)
value = iData(model, p, q, w)
input: p: spinwave model parameters set as '$par' symbols in the spinwave template (double)
q: axis along Q in [Angs-1] (row,double)
w: axis along energy in meV (column,double)
Crystal 4D case: Once created, the model is used as:
value = model(p, qh, qk, ql, w)
value = iData(model, p, qh, qk, ql, w)
input: p: spinwave model parameters set as '$par' symbols in the spinwave template (double)
qh: axis along QH in rlu (row,double)
qk: axis along QK in rlu (column,double)
ql: axis along QL in rlu (page,double)
w: axis along energy in meV (double)
signal: when values are given, a guess of the parameters is performed (double)
output: signal: model value
Example:
m = sqw_spinwave('defaults');
m = sqw_spinwave('MnFe4Si3.txt'); S=iData(m, [], 0:.05:4, 0,0, 0:0.5:20);
plot(log10(S));
m = sqw_spinwave('MnFe4Si3.txt','powder');
q = linspace(0.01:.25:3); w=0:.5:20;
S=iData(m, [], q, w); S=iData_Sqw2D(S);
Reference: SpinWave, S. Petit LLB <http://www-llb.cea.fr/logicielsllb/SpinWave/SW.html>
See also: read_cif, sqw_phonons, sqw_spinw