36 lines
1 KiB
Python
36 lines
1 KiB
Python
|
"""This module provides utilities for the whole package.
|
||
|
|
|
||
|
|
The defined constants are used as defaults in the Vector and Matrix classes.
|
||
|
|
|
||
|
|
The norm() function is shared by Vector.__abs__() and Matrix.__abs__().
|
||
|
|
"""
|
||
|
|
|
||
|
|
import math
|
||
|
|
|
||
|
|
|
||
|
|
# Define constants (i.e., normal variables that are, by convention, named in UPPERCASE)
|
||
|
|
# that are used as the defaults for class attributes within Vector and Matrix.
|
||
|
|
DEFAULT_ENTRIES_STORAGE = tuple
|
||
|
|
DEFAULT_ENTRY_TYPE = float
|
||
|
|
ZERO_THRESHOLD = 1e-12
|
||
|
|
|
||
|
|
|
||
|
|
def norm(vec_or_mat):
|
||
|
|
"""Calculate the Frobenius or Euclidean norm of a matrix or vector.
|
||
|
|
|
||
|
|
Find more infos here: https://en.wikipedia.org/wiki/Matrix_norm#Frobenius_norm
|
||
|
|
|
||
|
|
Args:
|
||
|
|
vec_or_mat (Vector / Matrix): object whose entries are squared and summed up
|
||
|
|
|
||
|
|
Returns:
|
||
|
|
norm (float)
|
||
|
|
|
||
|
|
Example Usage:
|
||
|
|
As Vector and Matrix objects are by design non-empty sequences,
|
||
|
|
norm() may be called, for example, with `[3, 4]` as the argument:
|
||
|
|
>>> norm([3, 4])
|
||
|
|
5.0
|
||
|
|
"""
|
||
|
|
return math.sqrt(sum(x ** 2 for x in vec_or_mat))
|