Refactor m_riemann_solvers Module (HLLC Solver Subroutine)

[Malmahrouqi3]

User description

Description

Reduced PR from (#855),

Essentially, I refactored math-critical items in s_hllc_riemann_solver subroutine.

---

PR Type

Enhancement

---

Description

• Consolidate variable initialization at loop start

• Merge duplicate loops for left/right state calculations

• Combine hypoelastic and hyperelastic energy adjustments

• Optimize Reynolds number computation loops

---

Changes diagram

flowchart LR
  A["Variable Initialization"] --> B["Loop Consolidation"]
  B --> C["Energy Adjustments Merge"]
  C --> D["Reynolds Number Optimization"]
  D --> E["Improved Code Structure"]

Loading

---

Changes walkthrough 📝

	Relevant files
Enhancement	m_riemann_solvers.fpp HLLC solver code structure optimization                                    src/simulation/m_riemann_solvers.fpp Consolidate variable initialization at beginning of loops Merge separate left/right state calculation loops into single loops Combine hypoelastic and hyperelastic energy adjustment logic Optimize Reynolds number calculations by merging loops +145/-264

---

Need help?

Type /help how to ... in the comments thread for any questions about Qodo Merge usage.

Check out the documentation for more information.

[qodo-merge-pro]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Logic Error In the merged loop for mpp_lim case, the left state normalization is now inside the same loop as the accumulation, which could cause incorrect calculations since alpha_L_sum is being modified while still being accumulated. do i = 1, num_fluids qL_prim_rs${XYZ}$_vf(j, k, l, i) = max(0._wp, qL_prim_rs${XYZ}$_vf(j, k, l, i)) qL_prim_rs${XYZ}$_vf(j, k, l, E_idx + i) = min(max(0._wp, qL_prim_rs${XYZ}$_vf(j, k, l, E_idx + i)), 1._wp) alpha_L_sum = alpha_L_sum + qL_prim_rs${XYZ}$_vf(j, k, l, E_idx + i) qR_prim_rs${XYZ}$_vf(j + 1, k, l, i) = max(0._wp, qR_prim_rs${XYZ}$_vf(j + 1, k, l, i)) qR_prim_rs${XYZ}$_vf(j + 1, k, l, E_idx + i) = min(max(0._wp, qR_prim_rs${XYZ}$_vf(j + 1, k, l, E_idx + i)), 1._wp) alpha_R_sum = alpha_R_sum + qR_prim_rs${XYZ}$_vf(j + 1, k, l, E_idx + i) end do !$acc loop seq do i = 1, num_fluids qL_prim_rs${XYZ}$_vf(j, k, l, E_idx + i) = qL_prim_rs${XYZ}$_vf(j, k, l, E_idx + i)/max(alpha_L_sum, sgm_eps) qR_prim_rs${XYZ}$_vf(j + 1, k, l, E_idx + i) = qR_prim_rs${XYZ}$_vf(j + 1, k, l, E_idx + i)/max(alpha_R_sum, sgm_eps) end do end if Duplicate Calculation The shear modulus G_L and G_R are calculated twice in the hyperelasticity branch - once at the beginning of the energy adjustment block and again specifically for hyperelasticity, leading to redundant computation. G_L = 0._wp; G_R = 0._wp; !$acc loop seq do i = 1, num_fluids ! Mixture left and right shear modulus G_L = G_L + alpha_L(i)*Gs(i) G_R = G_R + alpha_R(i)*Gs(i) end do Missing Assignment The missing assignment for Re_L(i) calculation completion in the viscous Reynolds number computation could lead to incorrect viscous flux calculations. Re_L(i) = 1._wp/max(Re_L(i), sgm_eps) Re_R(i) = 1._wp/max(Re_R(i), sgm_eps)

[Copilot]

Pull Request Overview

This PR refactors the s_hllc_riemann_solver subroutine in m_riemann_solvers.fpp to streamline variable initialization, consolidate energy adjustment logic, and introduce a loop_end helper for fluid loops.

• Consolidated zero-initialization of primitive-state variables at the start of each cell loop
• Merged hypoelastic and hyperelastic energy adjustments into a single conditional block
• Introduced loop_end to simplify fluid‐count branching

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	Remove duplicate shear modulus calculation The shear modulus calculation for G_L and G_R is duplicated in both the outer scope and within the hyperelasticity branch. Remove the redundant calculation inside the hyperelasticity branch to avoid unnecessary computation and potential inconsistency. src/simulation/m_riemann_solvers.fpp [1381-1431] if (hypoelasticity .or. hyperelasticity) then G_L = 0._wp; G_R = 0._wp !$acc loop seq do i = 1, num_fluids G_L = G_L + alpha_L(i)*Gs(i) G_R = G_R + alpha_R(i)*Gs(i) end do if (hypoelasticity) then ... else if (hyperelasticity) then ... - G_L = 0._wp; G_R = 0._wp; - !$acc loop seq - do i = 1, num_fluids - ! Mixture left and right shear modulus - G_L = G_L + alpha_L(i)*Gs(i) - G_R = G_R + alpha_R(i)*Gs(i) - end do + ! Elastic contribution to energy if G large enough + if (G_L > verysmall .and. G_R > verysmall) then + E_L = E_L + G_L*qL_prim_rs${XYZ}$_vf(j, k, l, xiend + 1) + E_R = E_R + G_R*qR_prim_rs${XYZ}$_vf(j + 1, k, l, xiend + 1) + end if ... end if end if Suggestion importance[1-10]: 6 __ Why: The suggestion correctly identifies that the calculation for G_L and G_R is duplicated, which is a code quality issue introduced in the PR.	Low
Update

[Malmahrouqi3]

Pushing this after ensuring select buggy tests that failed prior have passed neatly.

[codecov]

Codecov Report

Attention: Patch coverage is 22.22222% with 70 lines in your changes missing coverage. Please review.

Project coverage is 44.17%. Comparing base (6f58eec) to head (ec4151e).

Files with missing lines	Patch %	Lines
src/simulation/m_riemann_solvers.fpp	22.22%	66 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #912      +/-   ##
==========================================
+ Coverage   44.15%   44.17%   +0.02%     
==========================================
  Files          68       68              
  Lines       18347    18309      -38     
  Branches     2227     2225       -2     
==========================================
- Hits         8101     8088      -13     
+ Misses       8943     8922      -21     
+ Partials     1303     1299       -4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.