Files
solver/tests/test_newton.py
forbes-0023 98051ba0c9 feat: add Phase 1 constraint solver addon, move prior content to GNN/
- Move existing OndselSolver, GNN ML layer, and tooling into GNN/
  directory for integration in later phases
- Add Create addon scaffold: package.xml, Init.py
- Add expression DAG with eval, symbolic diff, simplification
- Add parameter table with fixed/free variable tracking
- Add quaternion rotation as polynomial Expr trees
- Add RigidBody entity (7 DOF: position + unit quaternion)
- Add constraint classes: Coincident, DistancePointPoint, Fixed
- Add Newton-Raphson solver with symbolic Jacobian + numpy lstsq
- Add pre-solve passes: substitution + single-equation
- Add DOF counting via Jacobian SVD rank
- Add KindredSolver IKCSolver bridge for kcsolve integration
- Add 82 unit tests covering all modules

Registers as 'kindred' solver via kcsolve.register_solver() when
loaded by Create's addon_loader.
2026-02-20 20:35:47 -06:00

89 lines
3.0 KiB
Python

"""Tests for the Newton-Raphson solver."""
import math
import pytest
from kindred_solver.expr import Const, Var
from kindred_solver.newton import newton_solve
from kindred_solver.params import ParamTable
class TestNewtonBasic:
def test_single_linear(self):
"""Solve x - 3 = 0 → x = 3."""
pt = ParamTable()
x = pt.add("x", 0.0)
residuals = [x - Const(3.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 3.0) < 1e-10
def test_single_quadratic(self):
"""Solve x^2 - 4 = 0 starting from x=1 → x = 2."""
pt = ParamTable()
x = pt.add("x", 1.0)
residuals = [x * x - Const(4.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 2.0) < 1e-10
def test_two_variables(self):
"""Solve x + y = 5, x - y = 1 → x=3, y=2."""
pt = ParamTable()
x = pt.add("x", 0.0)
y = pt.add("y", 0.0)
residuals = [x + y - Const(5.0), x - y - Const(1.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 3.0) < 1e-10
assert abs(pt.get_value("y") - 2.0) < 1e-10
def test_with_fixed(self):
"""Fixed parameter is not updated."""
pt = ParamTable()
x = pt.add("x", 0.0)
y = pt.add("y", 5.0, fixed=True)
residuals = [x + y - Const(10.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 5.0) < 1e-10
assert pt.get_value("y") == 5.0
def test_empty_system(self):
"""Empty residual list converges trivially."""
pt = ParamTable()
assert newton_solve([], pt) is True
class TestNewtonQuat:
def test_quat_renorm(self):
"""Quaternion re-normalization keeps unit length."""
pt = ParamTable()
qw = pt.add("qw", 0.9)
qx = pt.add("qx", 0.1)
qy = pt.add("qy", 0.1)
qz = pt.add("qz", 0.1)
# Residual: qw^2 + qx^2 + qy^2 + qz^2 - 1 = 0
r = qw * qw + qx * qx + qy * qy + qz * qz - Const(1.0)
quat_groups = [("qw", "qx", "qy", "qz")]
assert newton_solve([r], pt, quat_groups=quat_groups) is True
# Check unit length
w, x, y, z = (pt.get_value(n) for n in ["qw", "qx", "qy", "qz"])
norm = math.sqrt(w**2 + x**2 + y**2 + z**2)
assert abs(norm - 1.0) < 1e-10
class TestNewtonGeometric:
def test_point_coincidence(self):
"""Two points that should meet: (x,0,0) == (3,0,0)."""
pt = ParamTable()
x = pt.add("x", 0.0)
residuals = [x - Const(3.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 3.0) < 1e-10
def test_distance_constraint(self):
"""Point at (x,0,0) should be distance 5 from origin.
Squared: x^2 - 25 = 0, starting from x=3 → x=5."""
pt = ParamTable()
x = pt.add("x", 3.0)
residuals = [x * x - Const(25.0)]
assert newton_solve(residuals, pt) is True
assert abs(pt.get_value("x") - 5.0) < 1e-10