[liupengy19]

ParamParser::parse_expr splits an expression into terms at the last +/-, skipping only a sign right after * (as in pi*-0.25). A literal in scientific notation is therefore split at the sign of its exponent: rz(9.58737992428526e-05) is parsed as 9.58737992428526e minus 05, i.e. about 4.59 rad, without a warning. Likewise -4.79e-05 becomes about -9.79 and 3.451511e-09 about -5.55.

Such literals are common in generated circuits. For example, 15 circuits of the GUOQ benchmark suite (TFIM_step_*_4, TFIM_step_100_{8,16,32}, qft_20, vqe_4; 766 literals) contain them, so Quartz optimized a different circuit than the input.

Fix: also skip a +/- that follows e/E preceded by a digit or ..

Test: src/test/test_parser_exponent.cpp parses rz angles in scientific notation and the same angles written as plain decimals, and checks that the two circuits have the same matrix. On master 6 of the 7 cases fail; with the fix all pass. The changed files are clean under clang-format 21.1.0 (the pre-commit version).

Not changed here: with USE_RATIONAL (the default), string_to_param_without_pi stores a decimal angle as std::to_string(angle / pi), i.e. with 6 decimals, so small angles are still rounded (e.g. 9.587e-05 rad becomes 3.1e-05·π ≈ 9.74e-05 rad); the existing warning covers this.

🤖 Generated with Claude Code

https://claude.ai/code/session_01YFXDzXihmK8D9bNxsBNotC

[Copilot]

🟢 Approval recommended

No active review issues block approval of the scientific-notation parsing change.

No open issues 🎉

What changed in this PR

This PR fixes QASM parameter parsing so signs in scientific-notation exponents are not mistaken for addition or subtraction, preventing incorrect rotation angles in parsed circuits.

Changes:

• Preserve exponent signs following e or E when preceded by a digit or decimal point.
• Add seven matrix-equivalence regression cases covering scientific notation, subtraction, and existing negative-factor handling.
• Add a CMake executable target for the new regression test.

File	Description
src/​test/​test_parser_exponent.cpp	Compares circuits parsed from scientific-notation angles and equivalent expressions.
src/​test/​CMakeLists.txt	Adds the test_parser_exponent executable target.
src/​quartz/​parser/​qasm_parser.cpp	Skips exponent signs when splitting expressions into terms.

_{Review effort: Balanced}

[xumingkuan]

LGTM, thx