Files
solver/kindred_solver/params.py
forbes-0023 92ae57751f feat(solver): graph decomposition for cluster-by-cluster solving (phase 3)
Add a Python decomposition layer using NetworkX that partitions the
constraint graph into biconnected components (rigid clusters), orders
them via a block-cut tree, and solves each cluster independently.
Articulation-point bodies propagate as boundary conditions between
clusters.

New module kindred_solver/decompose.py:
- DOF table mapping BaseJointKind to residual counts
- Constraint graph construction (nx.MultiGraph)
- Biconnected component detection + articulation points
- Block-cut tree solve ordering (root-first from grounded cluster)
- Cluster-by-cluster solver with boundary body fix/unfix cycling
- Pebble game integration for per-cluster rigidity classification

Changes to existing modules:
- params.py: add unfix() for boundary body cycling
- solver.py: extract _monolithic_solve(), add decomposition branch
  for assemblies with >= 8 free bodies

Performance: for k clusters of ~n/k params each, total cost drops
from O(n^3) to O(n^3/k^2).

220 tests passing (up from 207).
2026-02-20 22:19:35 -06:00

84 lines
2.6 KiB
Python

"""Parameter table mapping named variables to Expr Var nodes and current values."""
from __future__ import annotations
from typing import Dict, List
import numpy as np
from .expr import Var
class ParamTable:
"""Central registry of solver variables.
Each parameter has a name, a current numeric value, an associated
:class:`Var` expression node, and a fixed/free flag. Grounded
body parameters are marked fixed so the pre-pass can substitute
them as constants.
"""
def __init__(self):
self._vars: Dict[str, Var] = {}
self._values: Dict[str, float] = {}
self._fixed: set[str] = set()
self._free_order: List[str] = [] # insertion-ordered free names
def add(self, name: str, value: float = 0.0, fixed: bool = False) -> Var:
"""Create a parameter and return its Var node."""
if name in self._vars:
raise ValueError(f"Duplicate parameter: {name}")
v = Var(name)
self._vars[name] = v
self._values[name] = value
if fixed:
self._fixed.add(name)
else:
self._free_order.append(name)
return v
def get_var(self, name: str) -> Var:
return self._vars[name]
def is_fixed(self, name: str) -> bool:
return name in self._fixed
def fix(self, name: str):
"""Mark a parameter as fixed and remove it from the free list."""
self._fixed.add(name)
if name in self._free_order:
self._free_order.remove(name)
def unfix(self, name: str):
"""Restore a fixed parameter to free status."""
if name in self._fixed:
self._fixed.discard(name)
if name not in self._free_order:
self._free_order.append(name)
def get_env(self) -> Dict[str, float]:
"""Return a snapshot of all current values (for Expr.eval)."""
return dict(self._values)
def free_names(self) -> List[str]:
"""Return ordered list of free (non-fixed) parameter names."""
return list(self._free_order)
def n_free(self) -> int:
return len(self._free_order)
def get_value(self, name: str) -> float:
return self._values[name]
def set_value(self, name: str, value: float):
self._values[name] = value
def get_free_vector(self) -> np.ndarray:
"""Current free-parameter values as a 1-D array."""
return np.array([self._values[n] for n in self._free_order], dtype=np.float64)
def set_free_vector(self, vec: np.ndarray):
"""Bulk-update free parameters from a 1-D array."""
for i, name in enumerate(self._free_order):
self._values[name] = float(vec[i])