Difference between revisions of "Spsk2mat.m"
m (Correct function page syntax from current Spinach source) |
(Add NOTOC to Spinach function page header) |
||
| Line 1: | Line 1: | ||
| − | {{DISPLAYTITLE:spsk2mat.m}} | + | {{DISPLAYTITLE:spsk2mat.m}} __NOTOC__ |
Converts span and skew representation of a 3x3 interaction tensor into the corresponding matrix. | Converts span and skew representation of a 3x3 interaction tensor into the corresponding matrix. | ||
Revision as of 16:59, 5 June 2026
Converts span and skew representation of a 3x3 interaction tensor into the corresponding matrix.
Syntax
M=spsk2mat(iso,sp,sk,alp,bet,gam)
Description
Isotropic part, span, and skew are often seen in the literature. It is not a good way of reporting an interaction tensor (the original matrix is best), but it is still being used.
Arguments
iso - isotropic part of the interaction, defined as
(xx+yy+zz)/3 in terms of eigenvaues
sp - interaction span, defined as the difference
between the largest and the smallest eigenvalue
sk - interaction skew, defined as 3*(yy-iso)/sp
where yy is the middle eigenvalue
alp - alpha Euler angle in radians
bet - beta Euler angle in radians
gam - gamma Euler angle in radians
Outputs
M - 3x3 matrix
Notes
The reverse transformation (from matrix into span, skew, and angles) is ill-defined.
See also
eeqq2nqi.m, castep2nqi.m, euler2dcm.m, xyz2dd.m, axrh2mat.m
Version 2.1, authors: Ilya Kuprov
