scipy.spatial.distance.

dice#

scipy.spatial.distance.dice(u, v, w=None)[source]#

Compute the Dice dissimilarity between two boolean 1-D arrays.

The Dice dissimilarity between u and v, is

\[\frac{c_{TF} + c_{FT}} {2c_{TT} + c_{FT} + c_{TF}}\]

where \(c_{ij}\) is the number of occurrences of \(\mathtt{u[k]} = i\) and \(\mathtt{v[k]} = j\) for \(k < n\).

Parameters:

u(N,) array_like, bool: Input 1-D array.
v(N,) array_like, bool: Input 1-D array.
w(N,) array_like, optional: The weights for each value in u and v. Default is None, which gives each value a weight of 1.0

Returns:

dicedouble: The Dice dissimilarity between 1-D arrays u and v.

Notes

This function computes the Dice dissimilarity index. To compute the Dice similarity index, convert one to the other with similarity = 1 - dissimilarity.

Examples

>>> from scipy.spatial import distance
>>> distance.dice([1, 0, 0], [0, 1, 0])
1.0
>>> distance.dice([1, 0, 0], [1, 1, 0])
0.3333333333333333
>>> distance.dice([1, 0, 0], [2, 0, 0])
-0.3333333333333333