我正在使用UMAP (https://umap-learn.readthedocs.io/en/latest/#) 来降低我的数据维度。我的数据集包含4700个样本,每个样本有120万个特征(我想要降低)。然而,即使使用了32个CPU和120GB的RAM,这仍然需要相当长的时间。特别是嵌入构建的过程很慢,而且冗长的输出在过去3.5小时内没有改变:
UMAP(dens_frac=0.0, dens_lambda=0.0, low_memory=False, n_neighbors=10,
verbose=True)
Construct fuzzy simplicial set
Mon Jul 5 09:43:28 2021 Finding Nearest Neighbors
Mon Jul 5 09:43:28 2021 Building RP forest with 59 trees
Mon Jul 5 10:06:10 2021 metric NN descent for 20 iterations
1 / 20
2 / 20
3 / 20
4 / 20
5 / 20
Stopping threshold met -- exiting after 5 iterations
Mon Jul 5 10:12:14 2021 Finished Nearest Neighbor Search
Mon Jul 5 10:12:25 2021 Construct embedding
有没有办法让这个过程更快?我已经按照这里所述使用了稀疏矩阵 (scipy.sparse.lil_matrix):https://umap-learn.readthedocs.io/en/latest/sparse.html。此外,我还安装了 pynndescent(如此处所述:https://github.com/lmcinnes/umap/issues/416)。我的代码如下:
from scipy.sparse import lil_matrix
import numpy as np
import umap.umap_ as umap
term_dok_matrix = np.load('term_dok_matrix.npy')
term_dok_mat_lil = lil_matrix(term_dok_matrix, dtype=np.float32)
test = umap.UMAP(a=None, angular_rp_forest=False, b=None,
force_approximation_algorithm=False, init='spectral', learning_rate=1.0,
local_connectivity=1.0, low_memory=False, metric='euclidean',
metric_kwds=None, n_neighbors=10, min_dist=0.1, n_components=2, n_epochs=None,
negative_sample_rate=5, output_metric='euclidean',
output_metric_kwds=None, random_state=None, repulsion_strength=1.0,
set_op_mix_ratio=1.0, spread=1.0, target_metric='categorical',
target_metric_kwds=None, target_n_neighbors=-1, target_weight=0.5,
transform_queue_size=4.0, unique=False, verbose=True).fit_transform(term_dok_mat_lil)
有没有什么技巧或想法可以使计算更快?我能改变一些参数吗?我的矩阵只由0和1组成(意味着矩阵中所有非零元素都是1),这会有所帮助吗?