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Fix PETSc error in mesh.adapt() with extra MeshVariables #67

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Merged
lmoresi merged 1 commit into from
Mar 3, 2026
Merged

Fix PETSc error in mesh.adapt() with extra MeshVariables #67

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48 changes: 20 additions & 28 deletions src/underworld3/discretisation/discretisation_mesh.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2961,13 +2961,12 @@ def adapt(self, metric_field, verbose=False):
print(f"[{uw.mpi.rank}] Notifying surface '{surface.name}' (marking distance stale)...", flush=True)
surface._on_mesh_adapted(self)

# Capture current variable data, excluding only the metric field
# (which becomes invalid after adaptation)
# All other variables (including surface distance fields) are reinitialized
# Capture all user-supplied variables for reinitialization on the new mesh.
# The metric field is included — it's a user-created variable that may
# have external references and be reused in subsequent adaptation cycles.
old_vars_data = {}
metric_name = metric_field.name if hasattr(metric_field, 'name') else None
for var_name, var in self._vars.items():
if var is not None and var_name != metric_name:
if var is not None:
old_vars_data[var_name] = var

# Stack boundary labels for adaptation
Expand Down Expand Up @@ -3054,27 +3053,26 @@ def mesh_update_callback(array, change_context):
# Rebuild coordinate navigation
self.nuke_coords_and_rebuild(verbose=False)

# Destroy ALL old vectors upfront before reinitializing any variable.
# This is critical because _setup_ds() iterates mesh._vars to backup/restore
# data — if some variables still hold lvecs with stale field_ids from the
# pre-adaptation DM, createSubDM will fail on the new DM. (Fixes #48)
for old_var in old_vars_data.values():
if old_var._lvec is not None:
old_var._lvec.destroy()
old_var._lvec = None
if old_var._gvec is not None:
old_var._gvec.destroy()
old_var._gvec = None
if hasattr(old_var, '_canonical_data'):
old_var._canonical_data = None
if hasattr(old_var, '_cached_data_array'):
old_var._cached_data_array = None

# Reinitialize MeshVariables on the new mesh
# Note: Variables are reset to zero. Users should reinitialize with data.
for var_name, old_var in old_vars_data.items():
try:
# Destroy old vectors
if old_var._lvec is not None:
old_var._lvec.destroy()
old_var._lvec = None
if old_var._gvec is not None:
old_var._gvec.destroy()
old_var._gvec = None

# Eagerly invalidate cached data arrays. The .data property also
# self-validates via _lvec identity check, but clearing here avoids
# unnecessary recreation on next access.
if hasattr(old_var, '_canonical_data'):
old_var._canonical_data = None
if hasattr(old_var, '_cached_data_array'):
old_var._cached_data_array = None

# Re-setup the variable on the new mesh
old_var._setup_ds()
old_var._set_vec(available=True)

Expand All @@ -3094,12 +3092,6 @@ def mesh_update_callback(array, change_context):
if verbose:
print(f"[{uw.mpi.rank}] Solver marked for rebuild", flush=True)

# Remove only the metric field from mesh._vars
# (it was specific to the pre-adaptation mesh and is now invalid)
# Surface distance variables stay - they're just marked stale and will recompute
if metric_name and metric_name in self._vars:
del self._vars[metric_name]

# Clear caches
self._evaluation_hash = None
self._evaluation_interpolated_results = None
Expand Down