Here is an example about how to quickly access the data from a coo_matrix
using the properties row
, col
and data
. The purpose of the example is just to show how to declare the data types and create the buffers (also adding the compiler directives that will usually give you a considerable boost)...
#cython: boundscheck=False
#cython: wraparound=False
#cython: cdivision=True
#cython: nonecheck=False
import numpy as np
from scipy.sparse import coo_matrix
cimport numpy as np
ctypedef np.int32_t cINT32
ctypedef np.double_t cDOUBLE
def print_sparse(m):
cdef np.ndarray[cINT, ndim=1] row, col
cdef np.ndarray[cDOUBLE, ndim=1] data
cdef int i
if not isinstance(m, coo_matrix):
m = coo_matrix(m)
row = m.row.astype(np.int32)
col = m.col.astype(np.int32)
data = m.data.astype(np.float64)
for i in range(np.shape(data)[0]):
print row[i], col[i], data[i]
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