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VASP Integration

MatClaw supports VASP (Vienna Ab initio Simulation Package) as an external computation engine. Since VASP is proprietary software, it is not bundled in the container — instead, you connect your existing VASP installation, and the agent executes VASP calculations seamlessly alongside the built-in open-source engines.

How It Works

User: "Calculate the band structure of GaAs using VASP with HSE06"
                          │
                          ▼
              Agent (inside container)
              ├─ Reads relevant skill guide
              ├─ Generates INCAR, POSCAR, KPOINTS, POTCAR
              ├─ Runs: vasp-remote run
              │   ├─ SSH mode: uploads files → submits job → polls → fetches results
              │   └─ Local mode: mpirun vasp_std directly
              └─ Parses vasprun.xml with pymatgen → returns band structure plot

The vasp-remote tool bridges the container and your VASP installation. It handles file transfer, job submission, status polling, and result retrieval — the agent just calls vasp-remote run and gets back the output files.

Two Connection Modes

SSH to HPC Cluster (Recommended)

Best for: users with access to a university/institute HPC cluster where VASP is installed.

Container ──SSH──▶ Login Node ──SLURM/PBS──▶ Compute Nodes
                                                  │
                                              vasp_std
                                                  │
                              ◀──SCP── vasprun.xml, OUTCAR, ...

The agent uploads VASP input files via SCP, submits a job through SLURM or PBS, waits for completion, and downloads the results. This is the most common setup — virtually all VASP users have cluster access.

Supported schedulers: SLURM (sbatch/squeue) and PBS (qsub/qstat).

Local VASP Binary

Best for: users with VASP installed on the same machine running MatClaw.

The host's VASP binary directory is volume-mounted into the container. The agent calls mpirun vasp_std directly.

Note: This mode requires that the container's MPI and library versions are compatible with the VASP binary compiled on the host. SSH mode avoids this issue entirely.

Setup

Run the /add-vasp skill in Claude CLI:

claude
# Then type: /add-vasp

The skill will interactively guide you through:

  1. Choosing connection mode (SSH or local)
  2. Entering cluster/binary details
  3. Testing the connection
  4. Rebuilding the container

SSH Mode Configuration

You'll need:

Field Example
SSH host login.hpc.example.edu
SSH user jdoe
SSH key ~/.ssh/id_rsa
VASP binary path (on cluster) /opt/vasp/6.4.3/bin/vasp_std
Scratch directory (on cluster) /scratch/jdoe/vasp-jobs
Scheduler slurm or pbs
Default cores 16

Local Mode Configuration

You'll need:

Field Example
VASP binary path /opt/vasp/bin/vasp_std
POTCAR directory /opt/vasp/potpaw_PBE
Number of cores 4

Usage

Once configured, VASP is available automatically. The agent chooses VASP when appropriate, or you can request it explicitly:

"Calculate the elastic constants of BaTiO3 using VASP"
"Run an HSE band structure for MoS2 with VASP"
"Relax the structure of Fe3O4 with VASP, use DFT+U"

The vasp-remote command is also available directly:

# Run VASP (blocking — waits for results)
vasp-remote run

# Run with custom settings
vasp-remote run --nprocs 32 --queue express --walltime 04:00:00

# Submit without waiting (SSH mode)
vasp-remote submit
# → Returns job_id

# Check status
vasp-remote status <job_id>

# Fetch results
vasp-remote fetch <job_id>

# Show configuration
vasp-remote config

VASP Is Optional

You do not need VASP to use MatClaw. All 213 computation skills provide up to three methods:

Method Engine Speed Accuracy Pre-installed
A ASE + MACE Seconds Screening Yes
B Quantum ESPRESSO Minutes–Hours Publication Yes
C VASP Minutes–Hours Publication No (optional)

Without VASP, the agent automatically uses Method A or B. VASP adds another high-accuracy option — particularly useful when you need VASP-specific features (hybrid functionals with VASP optimizations, specific pseudopotentials, compatibility with existing VASP workflows).

Troubleshooting

Problem Solution
vasp-remote: Config not found Run /add-vasp to configure
SSH connection refused Check VPN/firewall, verify with ssh -v user@host
Permission denied (publickey) Check key permissions: chmod 600 ~/.ssh/id_rsa
Job stuck in PENDING Try a different queue: vasp-remote run --queue express
vasp_std: command not found Verify VASP path: ssh user@host "ls /path/to/vasp_std"
Library errors (local mode) Switch to SSH mode to avoid container/host library mismatch