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- test_stitching_pad_mid_plane_close: solder-filled THT stitching pad mid-pour, adaptive vs uniform. Fails at 13.8% low on the pre-pinning adaptive path, passes at <0.1% with it. - normalize_decimal / parse_frequency: decimal commas parse, thousands- separator patterns raise instead of silently scaling 1000x. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
125 lines
4.7 KiB
Python
125 lines
4.7 KiB
Python
"""Skin-effect model tests. The single-layer AC solve scales ALL in-plane
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conductances identically, so R_AC = R_DC * resistance_factor EXACTLY -
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which turns the analytic foil formula into an end-to-end exact test."""
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import math
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import numpy as np
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import pytest
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from fill_resistance import raster, skin, solver
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from tests.util import NM, make_multilayer, strip_problem
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RHO = 1.68e-8
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def _solve(problem, h_mm, i_test=1.0, freq=0.0):
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stack = raster.rasterize_stack(problem, h_mm * NM)
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e1, e2 = raster.electrode_masks(stack, problem)
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return solver.run_solve(problem, stack, e1, e2, i_test, freq,
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contact_model="equipotential"), stack
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def test_skin_depth_value():
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# copper @ 1 MHz: ~65-66 um
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assert skin.skin_depth_m(1e6, RHO) * 1e6 == pytest.approx(65.2, rel=0.01)
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def test_sheet_resistance_dc_limit():
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t = 70e-6
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assert skin.sheet_resistance_ac(t, 0.0, RHO) == pytest.approx(RHO / t)
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# low frequency: within 0.1% of DC
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assert skin.sheet_resistance_ac(t, 100.0, RHO) == pytest.approx(
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RHO / t, rel=1e-3)
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def test_sheet_resistance_high_f_limits():
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t = 70e-6
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f = 1e9 # delta << t
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delta = skin.skin_depth_m(f, RHO)
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assert skin.sheet_resistance_ac(t, f, RHO, sides=1) == pytest.approx(
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RHO / delta, rel=0.01)
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assert skin.sheet_resistance_ac(t, f, RHO, sides=2) == pytest.approx(
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RHO / (2 * delta), rel=0.01)
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def test_resistance_factor_monotonic():
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t = 70e-6
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factors = [skin.resistance_factor(t, f, RHO)
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for f in (0, 1e4, 1e5, 1e6, 1e7, 1e8)]
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assert all(b >= a - 1e-12 for a, b in zip(factors, factors[1:]))
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assert factors[0] == 1.0
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def test_parse_frequency():
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assert skin.parse_frequency("") == 0.0
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assert skin.parse_frequency("0") == 0.0
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assert skin.parse_frequency("142k") == 142_000.0
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assert skin.parse_frequency("1.5M") == 1_500_000.0
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assert skin.parse_frequency("2meg") == 2_000_000.0
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assert skin.parse_frequency("100000") == 100_000.0
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assert skin.parse_frequency("100 kHz") == 100_000.0
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with pytest.raises(ValueError):
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skin.parse_frequency("junk") # must not silently become DC
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with pytest.raises(ValueError):
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skin.parse_frequency("-5k")
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def test_normalize_decimal():
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"""European decimal commas parse; thousands-separator patterns are
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rejected ('1,500' silently becoming 1.5 was a 1000x input error)."""
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assert skin.normalize_decimal("1,5") == "1.5"
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assert skin.normalize_decimal("0,25") == "0.25"
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assert skin.normalize_decimal("1,5000") == "1.5000" # 4 digits: decimal
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assert skin.normalize_decimal("2.5") == "2.5"
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for bad in ("1,500", "1.500,5", "1,000,000", "12,345"):
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with pytest.raises(ValueError, match="separator"):
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skin.normalize_decimal(bad)
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def test_parse_frequency_decimal_comma():
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assert skin.parse_frequency("1,5k") == 1500.0
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with pytest.raises(ValueError):
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skin.parse_frequency("1,500") # ambiguous, not 1.5 Hz
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def test_single_layer_ac_scales_exactly():
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"""Uniform conductance scaling leaves the field shape unchanged:
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R_AC = R_DC * factor to solver precision."""
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p = strip_problem(length=50, width=10, e_len=5)
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f = 2e6 # delta=46um < t=70um
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r_dc, _ = _solve(p, 0.5)
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r_ac, _ = _solve(p, 0.5, freq=f)
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factor = skin.resistance_factor(70e-6, f, RHO, sides=1)
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assert factor > 1.2 # real crowding at 2 MHz
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assert r_ac.R_ohm == pytest.approx(r_dc.R_ohm * factor, rel=1e-9)
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assert r_ac.rs_ratios[0] == pytest.approx(factor, rel=1e-12)
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assert r_ac.skin_depth_um == pytest.approx(
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skin.skin_depth_m(f, RHO) * 1e6, rel=1e-12)
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def test_via_chain_ac_exact():
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"""1D chain: layers scale by the foil factor, the barrel by the
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plating-wall factor - exact composition."""
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STRIP = [(0, 0), (10, 0), (10, 1), (0, 1)]
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p = make_multilayer(
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[[(STRIP, [])], [(STRIP, [])]],
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rect1_mm=(0, 0, 1, 1), rect2_mm=(9, 0, 10, 1),
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contact1="L0", contact2="L1",
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vias_mm=[(5.5, 0.5)], gap_mm=1.0)
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f = 2e6
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sig_ac = 1.0 / skin.sheet_resistance_ac(70e-6, f, RHO, sides=1)
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via_factor = skin.resistance_factor(18e-6, f, RHO, sides=2)
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r_via_dc = RHO * 1e-3 / (math.pi * 0.3e-3 * 18e-6)
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r_exact = (5 + 4) / sig_ac + r_via_dc * via_factor
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res, _ = _solve(p, 1.0, freq=f)
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assert res.R_ohm == pytest.approx(r_exact, rel=1e-9)
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def test_dc_default_unchanged():
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"""freq omitted -> identical to the pre-skin behavior."""
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p = strip_problem(length=50, width=10, e_len=5)
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res, _ = _solve(p, 0.5)
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assert res.freq_hz == 0.0
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assert res.skin_depth_um is None
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assert all(r == 1.0 for r in res.rs_ratios)
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