Files
tensorneat-mend/algorithms/numpy/utils.py
2023-05-05 14:19:13 +08:00

56 lines
1.7 KiB
Python

import numpy as np
I_INT = np.iinfo(np.int32).max # infinite int
def flatten_connections(keys, connections):
indices_x, indices_y = np.meshgrid(keys, keys, indexing='ij')
indices = np.stack((indices_x, indices_y), axis=-1).reshape(-1, 2)
# make (2, N, N) to (N, N, 2)
con = np.transpose(connections, (1, 2, 0))
# make (N, N, 2) to (N * N, 2)
con = np.reshape(con, (-1, 2))
con = np.concatenate((indices, con), axis=1)
return con
def unflatten_connections(N, cons):
cons = cons[:, 2:] # remove the indices
unflatten_cons = np.moveaxis(cons.reshape(N, N, 2), -1, 0)
return unflatten_cons
def set_operation_analysis(ar1, ar2):
ar = np.concatenate((ar1, ar2), axis=0)
sorted_indices = np.lexsort(ar.T[::-1])
aux = ar[sorted_indices]
aux = np.concatenate((aux, np.full((1, ar1.shape[1]), np.nan)), axis=0)
nan_mask = np.any(np.isnan(aux), axis=1)
fr, sr = aux[:-1], aux[1:] # first row, second row
intersect_mask = np.all(fr == sr, axis=1) & ~nan_mask[:-1]
union_mask = np.any(fr != sr, axis=1) & ~nan_mask[:-1]
return sorted_indices, intersect_mask, union_mask
def fetch_first(mask, default=I_INT):
idx = np.argmax(mask)
return np.where(mask[idx], idx, default)
def fetch_last(mask, default=I_INT):
reversed_idx = fetch_first(mask[::-1], default)
return np.where(reversed_idx == -1, -1, mask.shape[0] - reversed_idx - 1)
def fetch_random(rand_key, mask, default=I_INT):
"""
similar to fetch_first, but fetch a random True index
"""
true_cnt = np.sum(mask)
cumsum = np.cumsum(mask)
target = np.random.randint(rand_key, shape=(), minval=0, maxval=true_cnt + 1)
return fetch_first(cumsum >= target, default)