[WIP] Add Suzuki-Trotter to C API #15459

Estebanrg21 · 2025-12-17T07:22:22Z

Summary

This pull request implements the Suzuki-Trotter evolution within the C API.

Details and comments

1. New APIs:

The file with the implementation for the Suzuki-Trotter evolution at crates/circuit_library/src/suzuki_trotter.rs
The file with the implementation for the Suzuki-Trotter evolution at crates/synthesis/src/evolution/suzuki_trotter.rs
The file with the exposure of the Suzuki-Trotter evolution for the C API at crates/cext/src/synthesis/suzuki_trotter.rs

2. As part of the implementation, some APIs were made public:

modulesynthesis/evolution
Instruction struct from crates/circuit_library/src/pauli_evolution.rs
module crates/circuit_library/src/pauli_evolution.rs

3. The `qiskit-synthesis` and `qiskit-quantum-info` crates were added as dependencies for `qiskit-circuit-library`

CLAassistant · 2025-12-17T07:22:30Z

All committers have signed the CLA.

CLAassistant · 2025-12-17T07:22:30Z

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

Esteban Ramirez seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

Cryoris

Thanks for the PR @Estebanrg21, this already looks pretty good! I think we can improve the datastructures a bit and avoid some clones and collections.

This would also need a release note 🙂

Cryoris · 2025-12-19T14:33:12Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+    }
+}
+
+pub fn evolution(order: u32, mut paulis: Vec<StrSparseTerm>) -> Vec<StrSparseTerm> {


paulis shouldn't be mutable here if we're returning a new clone, also we can should be able to change this to take a slice (paulis: &[SparseTermView]) I believe

Cryoris · 2025-12-19T14:33:21Z

crates/circuit_library/src/suzuki_trotter.rs

+        )
+    }
+
+    let parsed_observable: Vec<StrSparseTerm> = observable


SparseObservable has a iter method which returns SparseTermView objects. These are pretty close to your StrSparseTerm here. Do you think we could directly use the SparseTermView to avoid cloning into a StrSparseTerm?

Cryoris · 2025-12-19T14:37:32Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+    };
+}
+
+pub fn reorder_terms<'a>(terms: &'a Vec<StrSparseTerm<'a>>) -> Vec<StrSparseTerm<'a>> {


You can just use a slice here, that's more generic

Suggested change

pub fn reorder_terms<'a>(terms: &'a Vec<StrSparseTerm<'a>>) -> Vec<StrSparseTerm<'a>> {

pub fn reorder_terms<'a>(terms: &'a [StrSparseTerm<'a>]) -> Vec<StrSparseTerm<'a>> {

Cryoris · 2025-12-19T14:40:17Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+                )
+            })
+            .collect_tuple()
+            .expect("Expected a combination of two values");


Since this is not a C-specific function, can we make it return a proper Result<..> type, such that errors could be handled gracefully? You could just start with a &str as error type.

Cryoris · 2025-12-19T14:41:40Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+}
+
+pub fn reorder_terms<'a>(terms: &'a Vec<StrSparseTerm<'a>>) -> Vec<StrSparseTerm<'a>> {
+    let sorted: Vec<&StrSparseTerm> = terms


You don't have to collect this into a vec if you're just iterating over it later, i.e, we can do

let mut graph = .. for term in terms.iter().sorted_by_key(..) { graph.add_node(term); }

Cryoris · 2025-12-19T14:42:02Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+        .sorted_by_key(|view| (view.indices, view.terms.clone()))
+        .collect();
+
+    let mut graph: Graph<&StrSparseTerm, Option<u8>, Undirected> = Graph::new_undirected();


Is there a way to tell the graph what capacity we need, such that we can allocate the required memory only one?

Cryoris · 2025-12-19T15:01:46Z

crates/synthesis/src/evolution/suzuki_trotter.rs

+    };
+}
+
+pub fn reorder_terms<'a>(terms: &'a Vec<StrSparseTerm<'a>>) -> Vec<StrSparseTerm<'a>> {


This function does a lot of collecting and cloning, that we should try to avoid. We could change e.g. to return the indices in which the terms should be applied instead of cloning and collecting into a new container.

Cryoris · 2025-12-19T15:03:19Z

crates/circuit_library/src/suzuki_trotter.rs

+    insert_barriers: bool,
+) -> Result<CircuitData, PyErr> {
+    if order > 1 && order % 2 == 1 {
+        panic!(


Same here, could we turn this into an error instead of a panic? Panics should be reserved for cases that should not be reached -- or for C functions where we can't handle errors gracefully 🙂

Cryoris · 2025-12-19T15:04:01Z

crates/cext/src/circuit_library/suzuki_trotter.rs

+
+#[unsafe(no_mangle)]
+#[cfg(feature = "cbinding")]
+pub extern "C" fn qk_circuit_library_suzuki_trotter_evolution(


Could we rename this to just qk_circuit_library_suzuki_trotter? The name is long enough then... 😄

Cryoris · 2025-12-19T15:04:17Z

crates/cext/src/circuit_library/suzuki_trotter.rs

+use qiskit_circuit_library::suzuki_trotter::suzuki_trotter_evolution;
+use qiskit_quantum_info::sparse_observable::SparseObservable;
+
+#[unsafe(no_mangle)]


This function needs a docstring, see the other C functions for examples

qiskit-bot added the Community PR PRs from contributors that are not 'members' of the Qiskit repo label Dec 17, 2025

Estebanrg21 force-pushed the qamp2025-29-esteban branch 7 times, most recently from f810558 to 2bac78e Compare December 17, 2025 07:57

Cryoris added this to the 2.4.0 milestone Dec 17, 2025

github-project-automation bot moved this to Ready in Qiskit 2.4 Dec 17, 2025

github-project-automation bot added this to Qiskit 2.4 Dec 17, 2025

Cryoris added the Changelog: New Feature Include in the "Added" section of the changelog label Dec 17, 2025

Add Suzuki-Trotter to C API

35783dd

Estebanrg21 force-pushed the qamp2025-29-esteban branch from 2bac78e to 35783dd Compare December 19, 2025 07:18

Cryoris reviewed Dec 19, 2025

View reviewed changes

Cryoris self-assigned this Dec 19, 2025

	pub fn reorder_terms<'a>(terms: &'a Vec<StrSparseTerm<'a>>) -> Vec<StrSparseTerm<'a>> {
	pub fn reorder_terms<'a>(terms: &'a [StrSparseTerm<'a>]) -> Vec<StrSparseTerm<'a>> {

[WIP] Add Suzuki-Trotter to C API #15459

Are you sure you want to change the base?

[WIP] Add Suzuki-Trotter to C API #15459

Conversation

Estebanrg21 commented Dec 17, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Details and comments

1. New APIs:

2. As part of the implementation, some APIs were made public:

3. The qiskit-synthesis and qiskit-quantum-info crates were added as dependencies for qiskit-circuit-library

Uh oh!

CLAassistant commented Dec 17, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

CLAassistant commented Dec 17, 2025

Uh oh!

Cryoris left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Estebanrg21 commented Dec 17, 2025 •

edited

Loading

3. The `qiskit-synthesis` and `qiskit-quantum-info` crates were added as dependencies for `qiskit-circuit-library`

CLAassistant commented Dec 17, 2025 •

edited

Loading