def CLJP(S, color=False):
"""Compute a C/F splitting using the parallel CLJP algorithm
Parameters
----------
S : csr_matrix
Strength of connection matrix indicating the strength between nodes i
and j (S_ij)
color : bool
use the CLJP coloring approach
Returns
-------
splitting : array
Array of length of S of ones (coarse) and zeros (fine)
Examples
--------
>>> from pyamg.gallery import poisson
>>> from pyamg.classical.split import CLJP
>>> S = poisson((7,), format='csr') # 1D mesh with 7 vertices
>>> splitting = CLJP(S)
See Also
--------
MIS, PMIS, CLJPc
References
----------
.. [1] David M. Alber and Luke N. Olson
"Parallel coarse-grid selection"
Numerical Linear Algebra with Applications 2007; 14:611-643.
"""
if not isspmatrix_csr(S):
raise TypeError('expected csr_matrix')
S = remove_diagonal(S)
colorid = 0
if color:
colorid = 1
T = S.T.tocsr() # transpose S for efficient column access
splitting = np.empty(S.shape[0], dtype='intc')
amg_core.cljp_naive_splitting(S.shape[0],
S.indptr, S.indices,
T.indptr, T.indices,
splitting,
colorid)
return splitting
def CLJP(S, color=False):
"""Compute a C/F splitting using the parallel CLJP algorithm
Parameters
----------
S : csr_matrix
Strength of connection matrix indicating the strength between nodes i
and j (S_ij)
color : bool
use the CLJP coloring approach
Returns
-------
splitting : array
Array of length of S of ones (coarse) and zeros (fine)
Examples
--------
>>> from pyamg.gallery import poisson
>>> from pyamg.classical.split import CLJP
>>> S = poisson((7,), format='csr') # 1D mesh with 7 vertices
>>> splitting = CLJP(S)
See Also
--------
MIS, PMIS, CLJPc
References
----------
.. [1] David M. Alber and Luke N. Olson
"Parallel coarse-grid selection"
Numerical Linear Algebra with Applications 2007; 14:611-643.
"""
if not isspmatrix_csr(S):
raise TypeError('expected csr_matrix')
S = remove_diagonal(S)
colorid = 0
if color:
colorid = 1
T = S.T.tocsr() # transpose S for efficient column access
splitting = numpy.empty(S.shape[0], dtype='intc')
amg_core.cljp_naive_splitting(S.shape[0],
S.indptr, S.indices,
T.indptr, T.indices,
splitting,
colorid)
return splitting
