Support hierarchical triple systems with dual binary components (BINARY + BINARY2) - #2011
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vhaasteren wants to merge 18 commits into
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Support hierarchical triple systems with dual binary components (BINARY + BINARY2)#2011vhaasteren wants to merge 18 commits into
BINARY + BINARY2)#2011vhaasteren wants to merge 18 commits into
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Enable a second (outer) binary delay component in a PINT timing model so a pulsar binary can itself orbit a third body. The outer orbit's delay is computed before, and propagated into, the inner binary calculation. - Make PulsarBinary suffix-aware (param_suffix, binary_param_tag, _bp/_hasbp helpers, _apply_param_suffix) so a single implementation serves as both the inner (canonical params) and outer (_2-suffixed params) component. - Route pb() and change_binary_epoch() through _bp()/_hasbp() so the inherited public methods work on suffixed outer components. - Add BinaryDD2 and BinaryBT2 outer wrappers (category pulsar_system_outer, param_suffix _2, BINARY2 tag). - Register BINARY2, order pulsar_system_outer before pulsar_system, and handle BINARY2 selection / validation in TimingModel and ModelBuilder. - Add triple-system par file and tests.
Select the primary binary component by binary_param_tag so orbital phase, pulsar radial velocity, and conjunction computations follow the inner BINARY orbit when BINARY2 is also present. Add a triple-system regression test that validates these utilities match the inner-only model and differ from the outer-orbit phase.
vhaasteren
marked this pull request as draft
June 30, 2026 09:03
A hierarchical triple's outer orbit imposes a slowly varying Doppler
factor on the inner orbit; over a short data span this appears as
secular changes of the inner A1 beyond the linear A1DOT term. A1DOT2
parameterizes the quadratic term:
a1(t) = A1 + A1DOT * (t - T0) + 0.5 * A1DOT2 * (t - T0)**2
Changes:
- new A1DOT2 floatParameter (lsec/s^2) on PulsarBinary, frozen at 0
when unset (BinaryDD.validate, like the other *DOT parameters)
- a1(), d_a1_d_T0, d_a1_d_A1DOT2 and d_Pobs_d_A1DOT2 in the standalone
PSR_BINARY (d_a1_d_T0 now includes the A1DOT2 chain term)
- d_beta_d_A1DOT2 in DDmodel for symmetry with d_beta_d_A1DOT (the
generic d_beta_d_par path chains through d_a1_d_par either way)
- tests: A1DOT2 affects the delay; analytic delay derivatives for
A1DOT2/A1DOT/T0 and outer parameters match finite differences
…t/triple Keep A1DOT2 with the X2DOT alias and retain local A1DOT2 tests.
Complete BINARY2 support for BT and ELL1 so A1DOT2 and the outer→inner prev-delay chain rule match finite-difference tests for all three families.
Chain-ruled d_delay_d_param requires SWX ahead of the binary; without solar_windx in DEFAULT_ORDER it sorted last and broke SW↔SWX fits. Also harden A1DOT parfile checks and Fermi observatory overwrite.
Compute parameter-independent acc_delays/chain_factors via delay_deriv_chain and thread them through designmatrix paths, restoring near-master cost while keeping the binary chain rule. Also harden triple-aware convert_binary, derived-param summary, and MissingParameter names.
…t/triple # Conflicts: # src/pint/models/stand_alone_psr_binaries/binary_generic.py # tests/test_triple_binary.py
Satisfy CI black --check, note solar_windx DEFAULT_ORDER in the changelog, and mention BINARY2 in timing-model docs.
Keep MissingParameter/MissingBinaryError/MissingTOAs re-exported from timing_model (listed in __all__) for existing importers. Remove a dead unreachable return in binary_generic.
Stop re-exporting them from timing_model; point remaining call sites at the canonical module.
vhaasteren
marked this pull request as ready for review
July 31, 2026 08:51
Stops collection failure in test_model_manual after Missing* stopped being re-exported from timing_model.
vhaasteren
added
enhancement
awaiting review
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Summary
BINARYwith standard parameter names (PB,A1,T0, ...)BINARY2with suffixed parameters (PB_2,A1_2,T0_2, ...)BinaryDD2,BinaryBT2) in a newpulsar_system_outercategory, ordered beforepulsar_systemso outer delay is accumulated first.t_bary - (accumulated delays), so the outer light-travel delay propagates into the inner orbit evaluation epoch.BINARY2, enforce one inner + one outer binary maximum, and round-trip_2parameters correctly._bp()/_hasbp()), enabling fitting and derivative support for outer-orbit parameters without changing standalone binary calculators.Scope / Notes
FBn/ORBWAVEparameterizations.Tests
outerbeforeinner)PBvsPB_2, etc.)BINARY2+_2parfile read/write round-tripExample
Note: co-developed by @coclar and Claude Code.