Arbitrary Order Trotter#389
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…d orders Co-authored-by: v-agamshayit <257422224+v-agamshayit@users.noreply.github.com>
…upported values (#385)
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
v-agamshayit
requested review from
ConradJohnston,
nabbelbabbel,
sobolevnrm and
wavefunction91
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Pull request overview
Adds support for even (arbitrary) order Trotter–Suzuki decompositions and extends step-count/error-bound estimation beyond first order, with expanded unit tests for the new orders.
Changes:
- Extend Trotter builder to generate order-2 and higher even-order product formulas (bottom-up construction).
- Extend naive and commutator-based step estimators to support order 2 and higher even orders (with a “largest Taylor coefficient” constant).
- Add/adjust tests for step estimation, decomposition correctness, and error-bound comparisons across orders.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 8 comments.
Show a summary per file
| File | Description |
|---|---|
| python/tests/test_trotter_error.py | Updates step-estimator tests to pass order and adds new order-2 / higher-order cases. |
| python/tests/test_time_evolution_trotter.py | Adds decomposition/correctness tests for order 2 and 4; updates unsupported-order behavior expectations. |
| python/src/qdk_chemistry/utils/pauli_commutation.py | Adds nested-commutator vanishing check and commutator bounds for order 2 and higher. |
| python/src/qdk_chemistry/algorithms/time_evolution/builder/trotter_error.py | Generalizes trotter_steps_* APIs and formulas to support order 2 and higher even orders. |
| python/src/qdk_chemistry/algorithms/time_evolution/builder/trotter.py | Implements general _trotter flow for even orders and computes a “largest error coefficient” for bounds. |
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
|
@v-agamshayit I've opened a new pull request, #390, to work on those changes. Once the pull request is ready, I'll request review from you. |
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Pull request overview
Copilot reviewed 5 out of 5 changed files in this pull request and generated 9 comments.
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Pull request overview
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Pull request overview
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This pull requests adds support for arbitrary order Trotter decompositions using the usual recursive definition. The computation of the terms and angles is done bottom-up using dynamic programming, which circumvents the exponential runtime complexity associated with recursion.
The implemented naive and commutator-based error bounds are extended to accommodate arbitrary p-order Trotter formulae. We use the asymptotic error estimate of Childs et.al 2021 (Theorem 6 and Corollary 7). New tests were added to ensure that the computed high-order formulae and their error bounds are correct.