def similarity_from_sparse(matrix_a: sparse.csr_matrix,
matrix_b: sparse.csr_matrix):
intersection = matrix_a.dot(matrix_b.transpose()).toarray()
norm_1 = np.array(matrix_a.multiply(matrix_a).sum(axis=1))
norm_2 = np.array(matrix_b.multiply(matrix_b).sum(axis=1))
union = norm_1 + norm_2.T - intersection
return intersection / union
def _compute_sparse_minimizer(hat_vect_matrix: sparse.csr_matrix,
X: sparse.csr_matrix) -> np.ndarray:
# compute numerator part of minimizer, this will yield a dense vector (size of u or v)
minimizer = (hat_vect_matrix.multiply(X)).sum(axis=1)
# divide by norm squared of masked vector
vector_of_norms = (hat_vect_matrix.multiply(hat_vect_matrix)).sum(axis=1)
# if some norm is 0 numerator will be 0 too (avoid 0/0)
vector_of_norms[vector_of_norms < 1e-8] = 1
minimizer = minimizer / vector_of_norms
# return np.ndarray representation
return minimizer.A
def fit(self, X: np.ndarray, knn: sparse.csr_matrix, k: int) -> np.ndarray:
"""
Args:
X Input vector of expression values, shape=(n_cells)
knn KNN connectivity matrix, shape=(n_cells, n_cells)
Remarks:
knn is assumed to have a single k for all cells (if not, the enrichment will
be only approximate).
"""
n_cells = X.shape[0]
nonzeros = (X > 0).astype('int')
nz_bycell = knn.multiply(nonzeros).sum(axis=1)
sum_bycell = knn.multiply(X).sum(axis=1)
total_nz = nonzeros.sum()
total_sum = X.sum()
nz_enrichment = (nz_bycell / k + self.epsilon) / ((total_nz - nz_bycell) / (n_cells - k) + self.epsilon)
mean_enrichment = (sum_bycell / k + self.epsilon) / ((total_sum - sum_bycell) / (n_cells - k) + self.epsilon)
return (nz_enrichment.A * mean_enrichment.A).T[0]
def normalize_adj(adj : sp.csr_matrix):
"""Normalize adjacency matrix and convert it to a sparse tensor."""
if sp.isspmatrix(adj):
adj = adj.tolil()
adj.setdiag(1)
adj = adj.tocsr()
deg = np.ravel(adj.sum(1))
deg_sqrt_inv = 1 / np.sqrt(deg)
adj_norm = adj.multiply(deg_sqrt_inv[:, None]).multiply(deg_sqrt_inv[None, :])
elif torch.is_tensor(adj):
deg = adj.sum(1)
deg_sqrt_inv = 1 / torch.sqrt(deg)
adj_norm = adj * deg_sqrt_inv[:, None] * deg_sqrt_inv[None, :]
return to_sparse_tensor(adj_norm)
def _compute_sparse_gradient(hat_vect_matrix: sparse.csr_matrix,
X: sparse.csr_matrix, z: np.ndarray,
y: np.ndarray) -> np.ndarray:
# grad_z = (hat_vect_matrix.multiply(z @ y.T - X)).sum(axis=1) <-- compressed but memory inefficient (`A`=z @ y.T is dense) implementation
# return grad_z.A
# sparse matrix are represented by data, rows, cols indices
sparse_X_tuple = (X.data, *X.nonzero())
# create difference matrix sparse representation to avoid passing `hat_vect_matrix` as full dense matrix
diff_matrix = sparse.csr_matrix(
(_compute_sparse_difference_matrix(sparse_X_tuple, z, y)),
shape=X.shape,
dtype=z.dtype)
# print("Norm-check", np.linalg.norm(hat_vect_matrix.multiply(diff_matrix).toarray() - hat_vect_matrix.multiply(z @ y.T - X).toarray() ) )
# sum over rows (axis=1)
return hat_vect_matrix.multiply(diff_matrix).sum(axis=1)
def Lloyd_iteration2( A,P, w ,Q):
dists,Tags,_=squaredis(P,Q)
print('finish squaredis')
Qjl=SM((Q.shape[0],A.shape[1]))
wq=np.zeros((Q.shape[0],1))
w=np.reshape(w,(len(w),1))
for i in range (Qjl.shape[0]):
#print(i)
inds=np.where(Tags==i)[0]
wmin=0
wi=w[inds,:]-wmin
Qjl[i,:]=(A[inds,:].multiply(wi)).sum(0)
wq[i,:]=np.sum(wi,0)
wq[wq==0]=1
wqi=1/wq
Qjl=Qjl.multiply(wqi+wmin)
return SM(Qjl)
def _assign_train_indices(self, tree: HuffmanTree, y: csr_matrix) -> HuffmanTree:
"""
Assings indices of train data to the nodes of the label tree.
:param tree: Label Tree
:param y: Label Matrix
:return: tree with data assigned
"""
if self.verbose:
print('Assigning train data to tree_ nodes')
for node in tree.bfs_traverse():
compare_row = np.zeros(y[0].shape).ravel()
compare_row[node.label_idx] = 1
compare_row = csr_matrix(compare_row)
# do matrix vector multiplication to
node.train_idx = y.multiply(compare_row)
node.y = node.train_idx.max(axis=1).astype('int8').toarray().ravel()
return tree
def __call__(self, matrix: csr_matrix):
SUM = matrix.sum()
row_sum = matrix.sum(axis=1)
col_sum = matrix.sum(axis=0)
# do: 1 / each cell
row_sum = _safe_divide(1, row_sum)
col_sum = _safe_divide(1, col_sum)
row_sum *= SUM
if self.smooth:
row_sum = np.power(row_sum, SMOOTH_POWER)
res = matrix.multiply(row_sum).multiply(col_sum).tocsr()
res.data = np.log(res.data)
res.eliminate_zeros()
return res
def sparse_average_precision_at_k(y_true: csr_matrix, y_scores: csr_matrix, k: int = 5) -> float:
"""
Computes the average precision at k for sparse binary matrices.
:param y_true: grounded truth in binary format (n_samples, n_labels)
:param y_scores: predictions in representation that can be ranked (e.g. probabilities)
:param k: top k labels to check
:return: precision at k score
"""
if y_true.shape != y_scores.shape:
raise Exception('y_true and y_pred must have same shape')
if y_true.shape[1] < k:
raise Exception('Less labels than k')
# get indices of k top values of y_pred
top_idx = top_n_idx_sparse(y_scores, k)
# create new matrix with shape == y_true.shape with only top ranked labels
y_pred_binary_only_top = lil_matrix(y_true.shape, dtype='int8')
for index, (binary_row, idx_row) in enumerate(zip(y_pred_binary_only_top, top_idx)):
y_pred_binary_only_top[index, idx_row] = 1
y_pred_binary_only_top = y_pred_binary_only_top.tocsr()
# compute precision
# get correct predicted labels
correct_labelled = y_true.multiply(y_pred_binary_only_top)
summed_precision = []
for index, (row, score_row) in enumerate(zip(correct_labelled, y_scores)):
# check special case that corresponding y_true row is empty => unlabeled instance
if y_true[index].count_nonzero() == 0:
# if no labels where predicted add 1 to sum
if score_row.count_nonzero() == 0:
summed_precision.append(1.0)
else:
summed_precision.append(0)
else:
summed_precision.append(row.count_nonzero() / k)
return sum(summed_precision) / len(summed_precision)
def compute_tf_idf(doc_matrix: sparse.csr_matrix) -> sparse.csr_matrix:
# 假设这里的 doc_matrix 已经是行和为 1，那么就只需计算 idf
# 首先找出所有非零元的坐标
i, nonzero_cols, v = sparse.find(doc_matrix)
# 然后统计每一列的非零元的个数
nonzero_cols, nonzero_col_appearences = np.unique(nonzero_cols,
return_counts=True)
# 有些列可能全为 0，所以
indicator = np.zeros(shape=(
1,
doc_matrix.shape[1],
), dtype=np.float32)
indicator[0, nonzero_cols] = nonzero_col_appearences[:]
n_articles = doc_matrix.shape[0]
indicator = np.log(n_articles / indicator)
# 此处为按元素乘
tf_idf = sparse.csr_matrix(doc_matrix.multiply(indicator))
return tf_idf
def compute_norms(matrix: sparse.csr_matrix) -> np.ndarray:
"""Computes norms for each row."""
return np.sqrt(matrix.multiply(matrix).sum(axis=1).A).flatten()
def sparse_pos_clip(a: csr_matrix):
# TODO: optimize
return a.multiply(a > 0)
def sparse_l2_norm(*, matrix: csr_matrix) -> np.array:
"""
Return the l2 norm of an input csr sparse matrix.
This is significantly faster and less memory intensive than simply passing the matrix to numpy.
"""
return np.sqrt(np.sum(matrix.multiply(matrix), axis=1))