FA-56019 / Astronomical coordinate conventions / Member archive

Pulsar phase polynomial: Instantaneous pulsar frequency is evaluated using phase polynomial coefficients · case 04

The adapter reports an incorrect frequency while other fields remain valid.

Member previewVariant 4 · 3 implementations · 6 checks per implementation

Case contract

A reduced pulsar timing model supplies elapsed barycentric time t, spin frequency f, first derivative fd, second derivative fdd, and phase zero p. Phase cycles are p+f*t+fd*t**2/2+fdd*t**3/6. Pulse numbering floors total phase, including negative epochs. Output fields are defined by: phase = d['p']+d['f']*d['t']+d['fd']*d['t']**2/2+d['fdd']*d['t']**3/6; frequency = d['f']+d['fd']*d['t']+d['fdd']*d['t']**2/2; frequency_derivative = d['fd']+d['fdd']*d['t']; pulse_number = int((d['p']+d['f']*d['t']+d['fd']*d['t']**2/2+d['fdd']*d['t']**3/6)//1); folded_phase = (d['p']+d['f']*d['t']+d['fd']*d['t']**2/2+d['fdd']*d['t']**3/6)%1; phase_residual = d['fd']*d['t']**2/2+d['fdd']*d['t']**3/6

Why this case matters

Catalog, detector, sky-coordinate, and spectroscopy adapters must preserve the association between numeric coordinates and their declared reference conventions.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
astronomical fixture 0	`{"folded_phase": 0.25, "frequency": 2, "frequency_derivative": 8, "phase": 84.25, "phase_residual": 72.0, "pulse_number": 84}`	`{"folded_phase": 0.25, "frequency": 32.0, "frequency_derivative": 8, "phase": 84.25, "phase_residual": 72.0, "pulse_number": 84}`	Failed

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