Source code for spyrmsd.utils
import os
import numpy as np
[docs]def format(fname: str) -> str:
"""
Extract format extension from file name.
Parameters
----------
fname : str
File name
Returns
-------
str
File extension
Notes
-----
The file extension is returned without the `.` character, i.e. for the file
`path/filename.ext` the string `ext` is returned.
If a file is compressed, the `.gz` extension is ignored.
"""
name, ext = os.path.splitext(fname)
if ext == ".gz":
_, ext = os.path.splitext(name)
return ext[1:] # Remove "."
[docs]def molformat(fname: str) -> str:
"""
Extract an OpenBabel-friendly format from file name.
Parameters
----------
fname : str
File name
Returns
-------
str
File extension in an OpenBabel-friendly format
Notes
-----
File types in OpenBabel do not always correspond to the file extension. This
function converts the file extension to an OpenBabel file type.
The following table shows the different conversions performed by this function:
========= =========
Extension File Type
--------- ---------
xyz XYZ
========= =========
"""
ext = format(fname)
if ext == "xyz":
# xyz files in OpenBabel are called XYZ
ext = "XYZ"
return ext
[docs]def deg_to_rad(angle: float) -> float:
"""
Convert angle in degrees to angle in radians.
Parameters
----------
angle : float
Angle (in degrees)
Returns
-------
float
Angle (in radians)
"""
return angle * np.pi / 180.0
[docs]def rotate(
v: np.ndarray, angle: float, axis: np.ndarray, units: str = "rad"
) -> np.ndarray:
"""
Rotate vector.
Parameters
----------
v: numpy.array
3D vector to be rotated
angle : float
Angle of rotation (in `units`)
axis : numpy.array
3D axis of rotation
units: {"rad", "deg"}
Units of `angle` (in radians `rad` or degrees `deg`)
Returns
-------
numpy.array
Rotated vector
Raises
------
AssertionError
If the axis of rotation is not a 3D vector
ValueError
If `units` is not `rad` or `deg`
"""
assert len(axis) == 3
# Ensure rotation axis is normalised
axis = axis / np.linalg.norm(axis)
if units.lower() == "rad":
pass
elif units.lower() == "deg":
angle = deg_to_rad(angle)
else:
raise ValueError(
f"Units {units} for angle is not supported. Use 'deg' or 'rad' instead."
)
t1 = np.outer(axis, np.inner(axis, v)).T
t2 = np.cos(angle) * np.cross(np.cross(axis, v), axis)
t3 = np.sin(angle) * np.cross(axis, v)
return t1 + t2 + t3
[docs]def center_of_geometry(coordinates: np.ndarray) -> np.ndarray:
"""
Center of geometry.
Parameters
----------
coordinates: np.ndarray
Coordinates
Returns
-------
np.ndarray
Center of geometry
"""
assert coordinates.shape[1] == 3
return np.mean(coordinates, axis=0)
[docs]def center(coordinates: np.ndarray) -> np.ndarray:
"""
Center coordinates.
Parameters
----------
coordinates: np.ndarray
Coordinates
Returns
-------
np.ndarray
Centred coordinates
"""
return coordinates - center_of_geometry(coordinates)