Propagator Functions¶

Propagate multiple propagators to a target epoch in parallel.

This function takes a list of propagators and calls propagate_to on each one in parallel using the global thread pool. Each propagator's internal state is updated to reflect the new epoch.

The list may freely mix KeplerianPropagator, SGPPropagator, and NumericalOrbitPropagator instances. Propagators are grouped by type and each group is propagated in parallel; results are written back to the original objects in place, preserving their order.

Note: NumericalPropagator (with user-defined Python dynamics) is NOT supported because Python callbacks cannot safely execute in parallel due to the GIL. Use NumericalOrbitPropagator for parallel propagation of orbital dynamics.

Note: For SGPPropagator and NumericalOrbitPropagator, event detectors and event logs are properly preserved during parallel propagation. Events detected during propagation will be available in each propagator's event_log() after the call completes.

Parameters:

Returns:

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import brahe as bh
import numpy as np

bh.initialize_eop()

epoch = bh.Epoch.from_datetime(2024, 1, 1, 0, 0, 0.0, 0.0, bh.TimeSystem.UTC)

# Create multiple propagators
propagators = []
for i in range(10):
    oe = np.array([bh.R_EARTH + 500e3 + i*10e3, 0.001, 98.0, i*10.0, 0.0, 0.0])
    state = bh.state_koe_to_eci(oe, bh.AngleFormat.DEGREES)
    prop = bh.KeplerianPropagator.from_eci(epoch, state, 60.0)
    propagators.append(prop)

# Propagate all to target epoch in parallel
target = epoch + 3600.0  # 1 hour later
bh.par_propagate_to(propagators, target)

# All propagators are now at target epoch
for prop in propagators:
    assert prop.current_epoch() == target