num_obs_linkage#
- scipy.cluster.hierarchy.num_obs_linkage(Z)[source]#
- Return the number of original observations of the linkage matrix passed. - Parameters:
- Zndarray
- The linkage matrix on which to perform the operation. 
 
- Returns:
- nint
- The number of original observations in the linkage. 
 
 - Notes - num_obs_linkagehas experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable- SCIPY_ARRAY_API=1and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.- Library - CPU - GPU - NumPy - ✅ - n/a - CuPy - n/a - ✅ - PyTorch - ✅ - ✅ - JAX - ✅ - ✅ - Dask - ✅ - n/a - See Support for the array API standard for more information. - Examples - >>> from scipy.cluster.hierarchy import ward, num_obs_linkage >>> from scipy.spatial.distance import pdist - >>> X = [[0, 0], [0, 1], [1, 0], ... [0, 4], [0, 3], [1, 4], ... [4, 0], [3, 0], [4, 1], ... [4, 4], [3, 4], [4, 3]] - >>> Z = ward(pdist(X)) - Zis a linkage matrix obtained after using the Ward clustering method with- X, a dataset with 12 data points.- >>> num_obs_linkage(Z) 12