| op_xyz_to_matrix {cry} | R Documentation |
Human-readable symmetry operator into matrix and vector
Description
Returns a 3\times 3 matrix and 3\times 1 vector corresponding to either a
symmetry operator or a centering operator in human-readable, string form.
Usage
op_xyz_to_matrix(op_xyz)
Arguments
op_xyz |
A symmetry or centering operation in the form of a human-readable string, e.g. -x+1/2,-y,z+1/2'. |
Details
A string describing a symmetry or a centering operation has a format similar to, for instance, '-x+1/2,-y,z+1/2'. Such a string corresponds to the symmetry operation represented mathematically by the following matrix and vector:
\left(\begin{array}{rrr}
-1 & 0 & 0 \\
0 & -1 & 0 \\
0 & 0 & 1
\end{array}\right)\quad,\quad
\left(\begin{array}{r}
1/2 \\
0 \\
1/2
\end{array}\right)
Where symmetry operations in human-readable form are useful for the subjective reasoning in crystallography, their mathematical counterpart is needed for all practical calculations.
Value
mat_ops A named list including a 3\times 3 matrix 'R' and a
3\times 1 vector 'T'.
Examples
# Reflection and translation
sop <- '-x,y+1/2,z'
mat_ops <- op_xyz_to_matrix(sop)
print(mat_ops)