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2a87ede | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | """
Real, per-machine qubit limits -- detects actual available RAM instead of
a number picked to fit whatever machine this was developed on. A modest
8 GB dev laptop and a 128 GB workstation get genuinely different limits.
Reuses dense_evolution.chunk.get_dynamic_chunk, the same real,
already-tested RAM-based sizing function the Chunk engine itself uses
(confirmed in feature/streamlit-dashboard's older simulation_runner.py:
"Decided by de.Chunk's own dynamic, available-RAM-based sizing... not a
hardcoded qubit-count constant, so it adapts to the machine it's running
on") -- rather than a second, slightly different hand-rolled formula.
The actual safety enforcement (rejecting a request that would genuinely
overflow RAM) is separate: dashboard_core.engine.run_circuit_from_qasm
calls dense_evolution.chunk.SafeMemoryGuard.check_allocation directly,
which has no floor -- this module is only the UI's suggested/default cap.
"""
import dense_evolution as de
__all__ = ['max_safe_dense_qubits']
def max_safe_dense_qubits() -> dict:
"""Suggested max qubit count for the Composer's Qubits field, from
dense_evolution.chunk.get_dynamic_chunk(complex128) -- floor 16,
ceiling 27 by that function's own design (a chunk always has *some*
minimum useful size, and 27 qubits/2 GB is its own practical ceiling
for a single dense block). MPS's contract_to_statevector has a
separate, RAM-independent hard ceiling of 24 qubits; picking 25-27
with the MPS backend surfaces that function's own real error rather
than being silently blocked here."""
guard = de.chunk.SafeMemoryGuard()
status = guard.status()
max_qubits = de.chunk.get_dynamic_chunk(de.chunk.jnp.complex128 if de.chunk.HAS_JAX else de.chunk.np.complex128)
return {
"total_mb": status["total_mb"],
"available_mb": status["available_mb"],
"threshold_pct": guard.threshold_pct,
"max_qubits_dense": max_qubits,
}
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