rand_binary_similarity#

skfp.distances.rand_binary_similarity(vec_a: ndarray | csr_array, vec_b: ndarray | csr_array) float#

Calculate the Rand binary similarity between two binary vectors.

Computes the Rand similarity [1] [2] (known as All-Bit [3] or Sokal-Michener) for binary data between two input arrays or sparse matrices using the formula:

\[sim(vec_a, vec_b) = |vec_a \cap vec_b| / n\]

where n is the length of vec_a.

The calculated similarity falls within the range [0, 1]. Passing all-zero vectors to this function results in a similarity of 0.

Parameters:
  • vec_a ({ndarray, sparse matrix}) – First binary input array or sparse matrix.

  • vec_b ({ndarray, sparse matrix}) – Second binary input array or sparse matrix.

Returns:

similarity – Rand similarity between vec_a and vec_b.

Return type:

float

References

Examples

>>> from skfp.distances import rand_binary_similarity
>>> import numpy as np
>>> vec_a = np.array([1, 0, 1])
>>> vec_b = np.array([1, 0, 1])
>>> sim = rand_binary_similarity(vec_a, vec_b)
>>> sim  
1.0
>>> from skfp.distances import rand_binary_similarity
>>> from scipy.sparse import csr_array
>>> vec_a = csr_array([[1, 0, 1]])
>>> vec_b = csr_array([[1, 0, 1]])
>>> sim = rand_binary_similarity(vec_a, vec_b)
>>> sim  
1.0