WillTools 2026-09-09 -- clean snapshot of the development repo for review

History-free snapshot of the private development repository at cbe45c5
(2026-09-09). Code, docs and public catalogue only; no plant or job
knowledge layers, no client or job names (tools/scrub.py clean). The
intro deck is left out of this snapshot because its slide images could
not be checked for job drawings.

panellift/tests/test_pci_fig832.py

@@ -0,0 +1,110 @@
+# -*- coding: utf-8 -*-
+"""The beam solver must reproduce PCI Figure 8.3.2 from first principles.
+
+This is the test the whole design rests on. Figure 8.3.2's coefficients are
+not a separate method -- they are the closed-form solution of a uniformly
+loaded beam with two overhangs, with the supports placed where the positive
+and negative moments come out equal. If our solver cannot land on 0.0214 with
+the supports there, it cannot be trusted with the supports somewhere else,
+which is the only case anyone actually needs it for.
+"""
+import math
+
+from panellift import pci, section, statics
+from panellift.model import Stage
+
+from conftest import ASPIRE, LENGTH_FT, WIDTH_FT
+
+
+def test_optimal_support_fraction_is_the_root_of_the_quadratic():
+    a = pci.OPTIMAL_TWO_LINE_FRACTION
+    assert abs(4 * a ** 2 + 4 * a - 1) < 1e-12
+    assert abs(a - 0.20710678) < 1e-7
+
+
+def test_closed_form_coefficient_is_pcis_0_0214():
+    """M = w*(aL)^2/2 with a = (sqrt(2)-1)/2 gives 0.02145, printed as 0.0214."""
+    a = pci.OPTIMAL_TWO_LINE_FRACTION
+    coefficient = a ** 2 / 2.0
+    assert abs(coefficient - 0.0214) < 0.0001
+
+
+def test_solver_reproduces_my_coefficient(solid_panel, rolling):
+    """The numerical diagram must match 0.0214 w a b^2 to within 0.5%."""
+    stage = Stage(name='unfactored', multiplier=1.0, fc_psi=4000.0)
+    result = statics.analyse(solid_panel, stage, rolling,
+                             reconcile_weight=False)
+
+    w_psf = section.unit_weight_psf(solid_panel)
+    _, expected = pci.fig_832_four_point(w_psf, WIDTH_FT, LENGTH_FT)
+
+    _, m_pos = result.diagram.max_positive
+    _, m_neg = result.diagram.max_negative
+
+    assert abs(m_pos - expected) / expected < 0.005
+    assert abs(abs(m_neg) - expected) / expected < 0.005
+
+
+def test_positive_and_negative_moments_are_equal_at_the_optimum(solid_panel,
+                                                                rolling):
+    """That equality is the definition of the Figure 8.3.2 layout."""
+    stage = Stage(name='unfactored', multiplier=1.0, fc_psi=4000.0)
+    result = statics.analyse(solid_panel, stage, rolling,
+                             reconcile_weight=False)
+    _, m_pos = result.diagram.max_positive
+    _, m_neg = result.diagram.max_negative
+    assert abs(m_pos - abs(m_neg)) / m_pos < 0.01
+
+
+def test_unit_weight_matches_the_article(solid_panel):
+    assert abs(section.unit_weight_psf(solid_panel) -
+               ASPIRE['w_psf']) < 0.1
+
+
+def _peak_abs_moment(result):
+    """The governing moment, whichever sign it has.
+
+    Bunching the picks inboard turns the panel into two long cantilevers, and
+    then the whole interior hogs -- the largest positive moment is zero, at
+    the ends. Comparing only sagging would read that as an improvement.
+    """
+    _, positive = result.diagram.max_positive
+    _, negative = result.diagram.max_negative
+    return max(abs(positive), abs(negative))
+
+
+def test_moving_the_supports_inboard_raises_the_governing_moment(solid_panel,
+                                                                 rolling):
+    """A sanity check that the solver is solving, not returning a constant."""
+    stage = Stage(name='unfactored', multiplier=1.0, fc_psi=4000.0)
+    optimum = _peak_abs_moment(
+        statics.analyse(solid_panel, stage, rolling, reconcile_weight=False))
+
+    for lifter in solid_panel.lifters:
+        lifter.x = LENGTH_FT / 2.0 + math.copysign(
+            4.0, lifter.x - LENGTH_FT / 2.0)
+    moved = _peak_abs_moment(
+        statics.analyse(solid_panel, stage, rolling, reconcile_weight=False))
+
+    assert moved > optimum * 1.5
+
+
+def test_the_optimum_layout_really_is_the_optimum(solid_panel, rolling):
+    """No other support position beats (sqrt(2)-1)/2. Worth proving once.
+
+    This is what makes the PCI layout a benchmark the report can measure a
+    detailer's actual layout against, rather than just another arrangement.
+    """
+    stage = Stage(name='unfactored', multiplier=1.0, fc_psi=4000.0)
+    best = _peak_abs_moment(
+        statics.analyse(solid_panel, stage, rolling, reconcile_weight=False))
+
+    for fraction in (0.10, 0.15, 0.18, 0.23, 0.26, 0.30):
+        left = fraction * LENGTH_FT
+        for lifter in solid_panel.lifters:
+            lifter.x = left if lifter.x < LENGTH_FT / 2.0 else LENGTH_FT - left
+        trial = _peak_abs_moment(
+            statics.analyse(solid_panel, stage, rolling,
+                            reconcile_weight=False))
+        assert trial >= best * 0.999, (
+            'fraction {0} beat the supposed optimum'.format(fraction))