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Allow other name for FLEX preconditioner #580

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Merged
merged 2 commits into from
Aug 7, 2025
Merged

Allow other name for FLEX preconditioner #580

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e392213
Allow other name for FLEX preconditioner
brownbaerchen Aug 6, 2025
8f5d569
Split generators for implicit and explicit preconditioners
brownbaerchen Aug 7, 2025
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45 changes: 21 additions & 24 deletions pySDC/core/sweeper.py
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Original file line number Diff line number Diff line change
Expand Up @@ -83,30 +83,27 @@ def __init__(self, params, level):
self.__level = level
self.parallelizable = False

def setupGenerator(self, qd_type):
def getGenerator(self, qd_type):
coll = self.coll
try:
assert QDELTA_GENERATORS[qd_type] == type(self.generator)
assert self.generator.QDelta.shape[0] == coll.Qmat.shape[0] - 1
except (AssertionError, AttributeError):
self.generator = QDELTA_GENERATORS[qd_type](
# for algebraic types (LU, ...)
Q=coll.generator.Q,
# for MIN in tables, MIN-SR-S ...
nNodes=coll.num_nodes,
nodeType=coll.node_type,
quadType=coll.quad_type,
# for time-stepping types, MIN-SR-NS
nodes=coll.nodes,
tLeft=coll.tleft,
)
except Exception as e:
raise ValueError(f"could not generate {qd_type=!r} with qmat, got error : {e}") from e

generator = QDELTA_GENERATORS[qd_type](
# for algebraic types (LU, ...)
Q=coll.generator.Q,
# for MIN in tables, MIN-SR-S ...
nNodes=coll.num_nodes,
nodeType=coll.node_type,
quadType=coll.quad_type,
# for time-stepping types, MIN-SR-NS
nodes=coll.nodes,
tLeft=coll.tleft,
)

return generator

def get_Qdelta_implicit(self, qd_type, k=None):
QDmat = np.zeros_like(self.coll.Qmat)
self.setupGenerator(qd_type)
QDmat[1:, 1:] = self.generator.genCoeffs(k=k)
self.genQI = self.getGenerator(qd_type)
QDmat[1:, 1:] = self.genQI.genCoeffs(k=k)

err_msg = 'Lower triangular matrix expected!'
np.testing.assert_array_equal(np.triu(QDmat, k=1), np.zeros(QDmat.shape), err_msg=err_msg)
Expand All @@ -117,8 +114,8 @@ def get_Qdelta_implicit(self, qd_type, k=None):
def get_Qdelta_explicit(self, qd_type, k=None):
coll = self.coll
QDmat = np.zeros(coll.Qmat.shape, dtype=float)
self.setupGenerator(qd_type)
QDmat[1:, 1:], QDmat[1:, 0] = self.generator.genCoeffs(k=k, dTau=True)
self.genQE = self.getGenerator(qd_type)
QDmat[1:, 1:], QDmat[1:, 0] = self.genQE.genCoeffs(k=k, dTau=True)

err_msg = 'Strictly lower triangular matrix expected!'
np.testing.assert_array_equal(np.triu(QDmat, k=0), np.zeros(QDmat.shape), err_msg=err_msg)
Expand Down Expand Up @@ -270,5 +267,5 @@ def updateVariableCoeffs(self, k):
k : int
Index of the sweep (0 for initial sweep, 1 for the first one, ...).
"""
if self.params.QI == 'MIN-SR-FLEX':
self.QI = self.get_Qdelta_implicit(qd_type="MIN-SR-FLEX", k=k)
if self.genQI._K_DEPENDENT:
self.QI = self.get_Qdelta_implicit(qd_type=self.genQI.__class__.__name__, k=k)