Tosca CLI Workflow Skill

This skill covers executing topology optimization via the Tosca CLI. For authoring the .par file (design responses, objectives, constraints, frozen regions), see the tosca skill. For the complete end-to-end topology optimization workflow (geometry through results), see /abaqus-topology-optimization.

When to Use This Skill

Route here when user mentions:

• "run optimization", "tosca optimize", "start tosca"
• "check run", "test run", "test1"
• "SLURM job", "submit to cluster", "CHPC", "sbatch"
• "optimization report", "convergence", "post-processing results"
• "smoothing", "STL export", "iso smoothing"
• "validation run", "run FEA on optimized design"
• "flatten inp", "renumber RP nodes"
• Debugging Tosca CLI errors (segfault, license, stale files)

Route elsewhere:

• Writing .par file content (DV_TOPO, DRESP, CONSTRAINT, etc.) -> tosca skill
• Complete topology optimization workflow -> /abaqus-topology-optimization
• Building the FEA model (geometry, mesh, BCs, loads) -> module skills
• CAE-based optimization API (TopologyTask, ObjectiveFunction) -> valid alternative for Abaqus built-in optimization; see /abaqus-topology-optimization for correct usage

Two Optimization Paths

Path A: CAE API (Abaqus built-in optimization)

The CAE optimization API (TopologyTask, ObjectiveFunction, OptimizationProcess) works correctly when used with the proper tuple format. The key pitfall: ObjectiveFunction.objectives must use 4-tuples (suppress, designResponse, weight, referenceValue). Passing a 5-tuple (e.g., with a trailing empty string) corrupts C++ state and causes segfaults/KeyErrors.

See /abaqus-topology-optimization for correct CAE API usage patterns.

Path B: Tosca CLI (primary workflow for this project)

For Tosca-specific features or standalone Tosca execution, the hybrid pipeline is used:

CAE Python API (noGUI)          Tosca CLI
--------------------------      ---------
1. Build geometry
2. Mesh
3. Material + section
4. Assembly, step, BCs, loads
5. noPartsInputFile=ON -------> 6. Generate .par file (hand-written)
   + writeInput()                7. tosca optimize -p file.par -s abaqus
                                 8. Output: ISO_SMOOTHING.stl

Note: Tosca .par files must be hand-written. CAE generates .par for its own optimization system, not for standalone Tosca.

Prerequisites

Before running Tosca CLI:

1. A flat .inp file (use noPartsInputFile=ON before writeInput())
2. A .par parameter file referencing the flat .inp
3. Full Abaqus license with Tosca module (not Learning Edition)
4. Tosca on PATH (tosca command available or abaqus tosca)

Workflow: Running Optimization

Step 1: Generate Flat .inp File

Tosca requires flat .inp files without Part/Instance/*Assembly hierarchy. Use noPartsInputFile=ON before writeInput():

mdb.models['Model-1'].setValues(noPartsInputFile=ON)
mdb.jobs[job_name].writeInput()

This produces a flat .inp directly — no manual flattening or RP node renumbering needed.

Legacy approach: If noPartsInputFile is not available, the .inp can be flattened manually. See references/common-patterns.md Pattern 1 and Pattern 2 for the legacy flattening code.

Step 2: Check Run (Test Before Optimizing)

ToscaStructure --job JOBNAME --solver abaqus --type test1

This validates the FE model and .par file without running a full optimization. Always do this first.

Step 3: Run Optimization

tosca optimize -j JOBNAME -p PARFILE -s abaqus -scpus N

Or equivalently:

ToscaStructure --job JOBNAME --solver abaqus

The .par file must reference the flattened .inp via FILE = flat.inp in its FEM_INPUT block. Both files must be in the current working directory or use absolute paths.

Step 4: Monitor Progress

• Watch JOBNAME/TOSCA.OUT for CRITICAL/ERROR/WARNING messages
• Check optimization_report.csv for per-cycle objective and constraint values
• Check optimizationstatusall.csv for extended convergence metrics

Step 5: Generate Report and Smooth Results

# Generate postprocessing report (.vtfx for visualization)
ToscaStructure --job JOBNAME --report

# Smooth results for CAD export (STL)
ToscaStructure --job JOBNAME --smooth

Step 6: Validation Run (FEA on Optimized Design)

Tosca deletes per-cycle ODB files. To visualize stress/displacement on the optimized design, run Abaqus FEA on the last-cycle .inp from SAVE.inp/<N>/:

cd JOBNAME/SAVE.inp/<last_cycle>/
abaqus job=Optimized input=flat.inp cpus=N interactive

The last-cycle .inp includes tosca_distribution.inp with per-element density values (SIMP penalties), so the FEA runs on the actual optimized topology.

Key CLI Flags

SLURM Integration

For HPC clusters, see references/common-patterns.md Pattern 3 for a complete SLURM script. Key considerations:

• module load abaqus/2025 (loads both Abaqus and Tosca)
• unset SLURM_GTIDS (prevents Abaqus MPI issues)
• export IMPIHYDRA_TOPOLIB=ipl (Intel MPI topology)
• Set ABAQUSNUMCPUS, ABAQUSMESHSIZE, etc. as environment variables
• Use Xvfb for visualization steps on headless nodes

Validation Checklist

After optimization completes:

• TOSCA.OUT shows no CRITICAL or ERROR messages
• optimization_report.csv shows objective converging
• Constraints satisfied in final cycle
• STL file produced (if SMOOTH block in .par)
• Validation FEA runs on last-cycle .inp without errors
• Stress/displacement results are physically reasonable

Troubleshooting

See references/troubleshooting.md for detailed error resolution.

Code Patterns

For actual code from the working experiments, see:

• [CLI Reference](references/cli-reference.md)
• [Common Patterns](references/common-patterns.md)
• [Troubleshooting Guide](references/troubleshooting.md)