Fix dichotomy for swe

[kahyami]

Please check if the PR fulfills these requirements (please use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes)

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem ? If so, link to this issue using '#XXX' and skip the rest

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

What is the current behavior? (You can also link to an open issue here)

What is the new behavior (if this is a feature change)?

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

Other information:

(if any of the questions/checkboxes don't apply, please delete them entirely)

Summary by CodeRabbit

• Bug Fixes
  • Improved dichotomy range calculations when starting from the maximum value.
  • Refined precision handling to stop searches correctly in edge cases.
  • Improved behavior when valid or invalid boundary values are unavailable.

[coderabbitai]

Walkthrough

HalfRangeDivisionIndexStrategy centralizes invalid-step bound selection for non-minimum-first searches and revises precision termination for asymmetric valid and invalid step states.

Changes

Half-range division strategy

Layer / File(s)	Summary
Bound selection and precision termination farao-dichotomy-api/src/main/java/com/farao_community/farao/dichotomy/api/index/HalfRangeDivisionIndexStrategy.java	The non-startWithMin path uses getInvalidStep(Index) for its upper bound, and precisionReached adds handling for missing invalid steps with an available highest valid step.

Estimated code review effort: 3 (Moderate) | ~15–30 minutes

Possibly related PRs

• farao-community/farao-dichotomy#94: Modifies the same strategy’s step-bound and precision handling.
• farao-community/farao-dichotomy#101: Updates the same non-startWithMin path and precision behavior.

Poem

A bunny bounds the halfway line,
With invalid steps kept neat and fine.
Precision checks now softly gleam,
Valid peaks guide the searcher’s dream.
Hop, hop—dichotomy’s bright!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title matches the main change: a fix to the dichotomy implementation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix_dichoto

Warning

Tools execution failed with the following error:

Failed to run tools: 13 INTERNAL: Received RST_STREAM with code 2 (Internal server error)

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

🧹 Nitpick comments (1)

farao-dichotomy-api/src/main/java/com/farao_community/farao/dichotomy/api/index/HalfRangeDivisionIndexStrategy.java (1)

48-51: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Use the local highestValidStep variable instead of calling index.highestValidStep() again.

Line 50 calls index.highestValidStep().getLeft() while the local variable highestValidStep (fetched at line 36 and null-checked at line 47) is already in scope. This is inconsistent with line 47 which uses the local variable, and introduces a potential correctness risk if the Index state changes between calls. Additionally, getInvalidStep(index) internally re-fetches index.lowestInvalidStep() which is already available as the local lowestInvalidStep from line 37.

♻️ Proposed refactor

         } else {
-            return mid(index.highestValidStep().getLeft(), getInvalidStep(index));
+            return mid(highestValidStep.getLeft(), getInvalidStep(index));
         }

For completeness, getInvalidStep could also accept the already-fetched lowestInvalidStep to avoid the redundant index.lowestInvalidStep() call:

-    private double getInvalidStep(Index<T> index) {
-        return index.lowestInvalidStep() != null
-                ? index.lowestInvalidStep().getLeft()
-                : index.maxValue();
+    private double getInvalidStep(Pair<Double, DichotomyStepResult<T>> lowestInvalidStep, double maxValue) {
+        return lowestInvalidStep != null
+                ? lowestInvalidStep.getLeft()
+                : maxValue;
     }

And update the call sites at lines 48 and 50 to pass lowestInvalidStep and maxValue.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In
`@farao-dichotomy-api/src/main/java/com/farao_community/farao/dichotomy/api/index/HalfRangeDivisionIndexStrategy.java`
around lines 48 - 51, Update the affected branch in
HalfRangeDivisionIndexStrategy to use the already-fetched, null-checked
highestValidStep variable instead of calling index.highestValidStep() again.
Also reuse the local lowestInvalidStep by updating getInvalidStep and its call
sites to accept that value, preserving the existing midpoint behavior.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In
`@farao-dichotomy-api/src/main/java/com/farao_community/farao/dichotomy/api/index/HalfRangeDivisionIndexStrategy.java`:
- Around line 48-51: Update the affected branch in
HalfRangeDivisionIndexStrategy to use the already-fetched, null-checked
highestValidStep variable instead of calling index.highestValidStep() again.
Also reuse the local lowestInvalidStep by updating getInvalidStep and its call
sites to accept that value, preserving the existing midpoint behavior.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e5274b9c-64ed-46c8-95bf-2311236f0cdc

📥 Commits

Reviewing files that changed from the base of the PR and between ed9f75c and c9f54d0.

📒 Files selected for processing (1)

• farao-dichotomy-api/src/main/java/com/farao_community/farao/dichotomy/api/index/HalfRangeDivisionIndexStrategy.java