Using Local Mantid Build in Other Projects with Pixi

Overview

This guide shows how to configure a pixi environment to use your local Mantid build instead of the conda package in other projects that depend on Mantid. This is useful when you need to develop and test changes across both Mantid and dependent applications simultaneously.

Prerequisites

  • A successfully built local Mantid installation (see Building with CMake)

  • Pixi installed

  • Your dependent project with pixi configuration

Configuration

Add a new pixi environment to your project’s pyproject.toml file:

[tool.pixi.environments]
local-mantid = { features = ["local-mantid"], solve-group = "default" }

[tool.pixi.feature.local-mantid.dependencies]
# Include your project's dependencies but exclude mantid packages
python = ">=3.10"
numpy = "*"
# ... other dependencies (do NOT include mantid, mantidworkbench, mantidqt)

[tool.pixi.feature.local-mantid.activation.env]
MANTID_BUILD_DIR = "/absolute/path/to/your/mantid/build"
MANTID_SOURCE_DIR = "/absolute/path/to/your/mantid/source"
PYTHONPATH = "${MANTID_BUILD_DIR}/bin:${MANTID_SOURCE_DIR}/Framework/PythonInterface:${MANTID_SOURCE_DIR}/qt/python/mantidqt"
LD_LIBRARY_PATH = "${MANTID_BUILD_DIR}/bin"        # Linux
DYLD_LIBRARY_PATH = "${MANTID_BUILD_DIR}/bin"      # macOS
MANTIDPATH = "${MANTID_BUILD_DIR}/bin"

[tool.pixi.feature.local-mantid.tasks]
# Launch local Mantid Workbench with your application
launch-local-workbench = { cmd = "cd $MANTID_BUILD_DIR/bin && ./launch_mantidworkbench.sh", description = "Launch local Mantid Workbench with your application available" }

Replace the paths with your actual Mantid build and source directories.

Usage

  1. Install the environment:

    pixi install --environment local-mantid

  2. Run your application:

    pixi run --environment local-mantid your-command

  3. Run Local Workbench in your application’s context:

    pixi run --environment local-mantid launch-local-workbench

Troubleshooting

Import errors: Verify PYTHONPATH includes ${MANTID_BUILD_DIR}/bin and your Mantid build completed successfully.

Library loading errors: Check that LD_LIBRARY_PATH (Linux) or DYLD_LIBRARY_PATH (macOS) includes ${MANTID_BUILD_DIR}/bin.

Path issues: Ensure all paths are absolute. Use realpath to resolve symbolic links if needed.

You can verify the environment setup with:

pixi run --environment local-mantid python -c "
import os, mantid
print('Mantid version:', mantid.__version__)
print('Mantid path:', mantid.__file__)
print('Build dir:', os.environ.get('MANTID_BUILD_DIR'))
"